Time-Series Trends of Trace Elements
in an Ice Core from Antarctica
by
SIDDIK SINAN KESKIN
M. S., Nuclear Engineering, The University of Michigan (1990)
B. S., Nuclear Energy Engineering, Hacettepe University, Rep. of Turkey (1986)
Submitted to the Department of Nuclear Engineering
in Partial Fulfillment of the Requirements for the
Degree of
DOCTOR OF PHILOSOPHY
in Nuclear Engineering
at the
Massachusetts Institute of Technology
September 1995
© 1995 Massachusetts Institute of Technology. All rights reserved.
Signature of Author...
.......................
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Department of Nuclear Engineering
July 6, 1995
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Certified by.......
-Dr.
D Ilhan Olmez
Principal Researc Scientist, Nuclear Reactor Laboratory
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Certified by.........
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Department of Geology at SUNY, Buffalo (Emeritus)
Thesis Reader
Accepted by ....................................
Prof. Jeffrey P. Freidberg
Department of Nuclear Engineering
Chairman Comjittee on Graduate Students
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APR 2 2 1996
TIME-SERIES TRENDS OF TRACE ELEMENTS
IN AN ICE CORE FROM ANTARCTICA
by
SIDDIK SINAN KESKIN
Submitted to the Department of Nuclear Engineering on July 6, 1995
in partial fulfillment of the requirements for the degree of
Doctor of Philosophy in Nuclear Engineering
ABSTRACT
Trace element measurements were made by instrumental neutron activation analysis on
stratigraphically dated ice core samples from Byrd Station, Antarctica, to determine the concentration
levels of natural and anthropogenic substances. Sampling was continuous between 1926 A.D. and 1989
A.D. and selective between 1711 A.D. and 1926 A.D. Twenty-one elements with concentrations above
the detection limits were determined.
The time period between 1969 A.D. and 1989 A.D. showed an enhanced impact on the Antarctic
ice sheets from natural sources in the form of marine and crustal aerosols. A disturbed ocean-atmosphere
interface due to El Niflo Southern Oscillation (ENSO) events seems to be a candidate especially for the
enhanced marine aerosol deposition in Antarctica.
Time-series trend of the concentration of deposited aluminum, which is mainly a crustal aerosol
related element, shows a strong negative correlation with the time-series trend of annual average total
column ozone concentrations homogenized between the 600 S and 900 S latitudes from the Total Ozone
Mapping Spectrometer (TOMS) ozone data set. Although the time period is not long enough to draw a
strong conclusion (1979-1989), the special role of crustal origin clay minerals on cloud nucleation
dynamics might be a factor in the heterogeneous stratospheric ozone depletion chemistry through polar
stratospheric cloud dynamics, assuming some troposphere-stratosphere mixing of these aerosols.
The correlation of antimony and arsenic enrichments with known or suspected volcanic events
was established. These marker elements was shown to be useful especially for the identification of
specific historical volcanic events with low sulfur emissions.
Although a clear anthropogenic impact was not observed, concentrations of arsenic, chromium,
and zinc, which might come from both natural and anthropogenic sources, indicated an increase after
1960's.
Principal component factor analysis indicated a possible transition-metal (especially manganese
and iron) catalyzed bromine chemistry cycle, which has been suggested as the cause of tropospheric
surface-level ozone depletion observed in Greenland.
Calculated snow-to-air scavenging ratios indicated more efficient scavenging for crustal aerosols
followed by marine and volatile elements.
A new method was developed for direct air content determination in small deep ice core samples
through the measurement of enclosed argon gas by instrumental neutron activation analysis.
Thesis Supervisor: Dr. Ilhan Olmez
Title: Principal Research Scientist, MIT Nuclear Reactor Laboratory, and
Department of Nuclear Engineering
Thesis Reader: Prof. Chester C. Langway, Jr.
Title: Professor of Geology, SUNY, Buffalo (Emeritus)
BIOGRAPHICAL SKETCH
Name:
SIDDIK SINAN KESKIN
Born:
August 31, 1964; Artvin, Republic of Turkey
Education:
Doctor of Philosophy in Nuclear Engineering, Massachusetts Institute of Technology. September 1995.
Thesis Title: Time-Series Trends of Trace Elements in an Ice Core from Antarctica.
Master of Science in Nuclear Engineering, The University of Michigan, May 1990.
Bachelor of Science in Nuclear Energy Engineering, Hacettepe University, Republic of Turkey, June 1986.
High School, Haydarpasa Teknik Lisesi, Republic of Turkey, June 1982.
Employment:
Arcelik, Kocaeli, Republic of Turkey,
Summer 1981
Arcelik, Kocaeli, Republic of Turkey,
Summer 1980
Super Elektrik, Istanbul, Republic of Turkey,
Summer 1979
Publications and Presentations:
Keskin, S.S., I. Olmez, and C.C. Langway, Jr., "Time-Series Analysis of Chemical Trends in a Dated Ice
Core from Antarctica", (Abstract), American Nuclear Society, Winter Meeting, November 13-17, 1994,
Washington, D.C.
Keskin, S.S., C.C. Langway, Jr., and I. Olmez, "Trace Elements in Dated Ice Cores From Antarctica and
Greenland", paper presented at the Second International Conference on Managing Hazardous Air
Pollutants, July 13-15, 1993, Washington, D.C.
Keskin, S.S., X. Huang, I. Olmez, and C.C. Langway, Jr., "Trace Elements in a Dated Ice Core From
Antarctica", (Abstract), American Nuclear Society, National Meeting, June 7-12, 1992, Boston, MA.
Huang, X., S. Keskin, I. Olmez, and G.E. Gordon, "Automobiles:Possible Sources of Metals Other Than
Lead in the Urban Atmosphere", (Abstract), American Nuclear Society, National Meeting, June 7-12,
1992, Boston, MA.
Olmez, I., X. Huang, S. Keskin, G.E. Gordon, and J. Ondov, "New Markers and Source Composition
Library for Motor Vehicle Emissions", American Chemical Society, National Meeting, April 5-10, 1992,
San Francisco, CA.
ACKNOWLEDGMENTS
I would like to thank to the Turkish Ministry of Education for giving me the chance to come to
the United States for my graduate study and providing financial support during my early years.
Further financial support during this research came from the different projects that I have
participated in as a research assistant for the Environmental Research and Radiochemistry Division.
I am grateful to my thesis supervisor Dr. Ilhan Olmez for his trust, encouragement, and constant
support during these years. He has been a good friend and a serious teacher who was always able to
convince me to volunteer to do more. His vision and will to pursue research in diverse fields has always
impressed me as a colleague.
I am also grateful to my thesis reader Professor Chester C. Langway, Jr. for his cooperation and
help during this research. He opened the way to this research by providing the samples used and letting
me use his laboratory at SUNY, Buffalo. His tremendous experience in the field of glaciology was always
an assurance.
I also thank to my thesis committee members Prof. Otto K. Harling, Prof. Norman C. Rasmussen,
Prof. Jacquelyn C. Yanch, and Prof. Sidney Yip for their critiques and suggestions during this research.
I would like to thank Thomas J. Langway, Kazuo Osada, and Ronald Wentzek of the Ice Core
Laboratory at SUNY, Buffalo for their help during sample preparation in their laboratory.
Special thanks to the MITR-II operations staff for their help during the sample irradiations.
Thanks are also due to the NRL machine shop staff for their help. The Nuclear Reactor Laboratory and
Nuclear Engineering Department staff deserve credit for their assistance during my stay at MIT.
Particular thanks to Rachel Morton for being a resource about computational issues.
I would like to mention my sincere appreciation to my friends and colleges Michael Ames,
Jianmei Che, Jec-Kong Gone, Xudong Huang, and Rena Lee at the Environmental Research and
Radiochemistry laboratory for their friendship and help during all these years. It was a close family away
from home that I always enjoyed to be a part of.
Amory Wakefield deserves special thanks for her help in data handling and grammatical
corrections at various stages. Karl Sebelius was also a help in some of the data handling tasks.
Special thanks are also due to visiting scientists Namik K. Aras, Jack Beal, Richard D. Fink,
Gulen Gullu, and Francis Pink for their friendship and helpful discussions.
I would like to thank Prof. Otto K. Harling, Prof. Alan F. Henry, and Prof. Mujid S. Kazimi for
their help and trust during my early years at MIT.
My countrymen and friends Huseyin Akcay, Ulfet Atav, Tamer Bahadir, Erol Cubukcu, Oguz
Ertugrul, Mehmet Gozcu, Tugrulbey Kiryaman, Volkan Kubali (and his notebook computer), Ata Mugan,
Cetin Ozbutun, Sadettin and Asuman Ozturk, Yuksel and Asuman Parlatan, Ilker and Sibel Tari, Mehmet
Tombakoglu, Ibrahim Ucok, and Serhat Yesilyurt deserve particular thanks for their friendship and
support during my stay in this country.
My former and current housemates Patrick Donnally, Salvatore Galea, Eric M. Jordan, Matthew
Marjanovic, Diane Ronan, and Kaoru Takase also deserve special thanks for their friendship.
Prof. Osman K. Kadiroglu and Prof. Yalcin Sanalan of Nuclear Energy Engineering at the
Hacettepe University deserve very special thanks for introducing me to this field and preparing me for the
future. As this is the formal end of my career as a student, I would like to mention my appreciation to all
of my previous teachers who did their best to prepare me for life as a member of humanity.
Finally, I am very much grateful to my mother Sennur Keskin, my father Fikret Keskin, my
sisters Aysu Keskin and Ayse Keskin, and my brother M. Gokhan Keskin for their continuing love and
support throughout my life. God's guidance and their existence made my life joyful and fulfilling. To
show my sincere appreciation, I am dedicating this thesis to them.
TABLE OF CONTENTS
.......................................
A B STR A C T .......................................................................
.............................
BIOGRAPHICAL SKETCH......................................................
...........................................
ACKNOW LEDGM ENTS........................................
............................
TABLE OF CONTENTS................................
LIST O F FIG U RES.............................................. ......................................................
LIST O F TA BLES............................................... .......................................................
1.
IN TR O DU C TIO N ..................................................................
1.1.
1.2.
1.3.
1.4.
1.5.
2.
3.
2
3
4........
5
7
9
........................ 11
11
.................................................
B ackground......................................
A Brief History of Antarctic Research....................................14
..... 15
NBY-89 Ice Core Research Program................................
Scope of Research................................................... 19
Basic Theory of the Instrumental Neutron Activation Analysis.............23
EXPERIM ENTAL................. .................................................................. 26
26
26
29
30
2.1.
........
Sample Selection and Preparation..............................
........ .....................
2.1.1. Selection.......................................................
........... ............
2.1.2. Preparation.............................................
.....
2.1.3. Pre-concentration by Freeze-drying........................
2.2.
... 33
Instrumental Neutron Activation Analysis..............................
........... ............ 33
2.2.1. Irradiations.............................................
....... 35
2.2.2. Gamma-Ray Spectroscopy..............................
2.2.3. Blank Correction..............................................38
2.3.
Air Content Determination.........................................40
RESULTS AND DISCUSSION.............................................44
3.1.
Data Quality Assessm ent..................................................................... 44
3.2.
Time-Series Trends..............................................................
3.2.1.
3.2.2.
3.2.3.
3.2.4.
3.2.5.
...................
51
........ 53
The Marine Aerosols...................................
Possible El Nifio Events-Marine Aerosols Connection............. 60
Crustal Aerosols and Their Possible Role in Polar Atmosphere....67
The Volcanic Aerosols................................................................. 78
...... 90
The Anthropogenic Aerosols................................
5
3.3.
Source Characterization........................................
..........
.......... 96
..... 96
3.3.1. Source-Receptor Relationship.............................
Factor
Analysis...............................98
3.3.2. Principal Component
3.4.
Air/Snow Partitioning..........................................
.........
.......... 107
3.4.1. Current State of Knowledge............................
3.4.2. Scavenging Ratios...............................
3.5.
4.
5.
Air Content Analysis................................................................................
107
112
16
SUMMARY AND SUGGESTIONS FOR FUTURE WORK.....................1.......19
4.1.
Summary.........................................................119
4.2.
Suggestions for future work...........................................
REFERENCES...............................
122
125
APPENDIX A.
Elemental concentrations and related statistical information....... 135
APPENDIX B.
Crustal and marine Enrichment Factors.................................
APPENDIX C.
Data tables for the samples obtained from volcanic eruption
horizons and a Rare Earth Elements anomaly horizon............ 183
APPENDIX D.
Basic theory of the Principal Component Factor Analysis...........188
APPENDIX E.
A brief review of the heterogeneous stratospheric ozone
.......
depletion chemistry............................ ...... .
163
204
LIST OF FIGURES
Figure 1-1.
Map of Antarctica and major ice coring sites..................................
Figure 1-2.
Illustration of (n,y) reaction followed by positron decay..........................23
Figure 2-1.
Schematic illustration of ice sample surface cleaning setup....................30
Figure 2-2.
Schematic illustration of the freeze-drying system.............................
Figure 2-3.
An example gamma-ray spectrum for ice core samples after ten
minutes irradiation...............................................
..........
16
32
.......... 37
Figure 2-4.
Illustration of air-free ice production system...................40
Figure 2-5.
Illustration of Air standard vial volume determination........................
Figure 2-6.
Illustration of ice sample selection for air content measurement............42
Figure 3-1.
Sketch of sampling system for cross-profiling sample preparation............45
Figure 3-2.
Elemental concentrations measured in cross-profiling samples..............47
Figure 3-3.
Sea-salt sodium (Nass) concentrations time-series trend.......................54
Figure 3-4.
Sodium and chlorine concentrations time-series trends.........................55
Figure 3-5.
Chlorine-to-sodium ratio time-series trend................................
Figure 3-6.
El Nifio events after 1926.................................
Figure 3-7.
The power spectrum of the sea-salt sodium time-series data.................64
Figure 3-8.
Sea-salt sodium time-series trend together with 4.2 year period fit
41
... 59
61
............
based on the analysis with The Linear Least Squares Spectral
Analysis (LLSSA) method....................................................................
Figure 3-9.
65
Sea-salt sodium time-series trend together with the top eight period fit
based on the analysis with The Linear Least Squares Spectral Analysis
(LLSSA ) m ethod.................................................................................
66
69
.........................
Figure 3-10.
Aluminum concentrations time-series trend..............
Figure 3-11.
Aluminum and scandium concentrations time-series trends...................70
Figure 3-12.
Scandium crustal Enrichment Factors time-series trend.........................71
Figure 3-13.
Annual average total column ozone (600 S-900 S) and aluminum
concentrations time-series trends.................................
Figure 3-14.
...... 75
Antimony and arsenic crustal Enrichment Factors time-series trends........80
81
Figure 3-15.
Antimony and arsenic concentrations time-series trends......................
Figure 3-16.
Lanthanum, Cerium, and Samarium crustal Enrichment Factors time-series
trends.....................................................
........................................... 86
Figure 3-17.
Excess antimony concentrations time-series trend.................................92
Figure 3-18.
Excess arsenic concentrations time-series trend.................................
93
Figure 3-19.
Excess zinc concentrations time-series trend...................................
94
Figure 3-20.
Excess chromium concentrations time-series trend...............................95
Figure 3-21.
Schematic of source-receptor relationship...........................
.... 97
Figure 3-22.
Factor Scores results for the first factor...............................
101
Figure 3-23.
Factor Scores results for the second factor............................................102
Figure 3-24.
Factor Scores results for the third factor...............................
Figure 3-25.
Factor Scores results for the fourth factor................................... 104
Figure 3-26.
Air-to-snow scavenging ratios for the elements Al, Fe, La, Na,
Zn, Sb, and As ....................................
.... 103
115
Figure A-1.
Cumulative percent data versus overall relative uncertainty..................136
Figure D- 1.
Sample vector space with three factors and five data column vectors.....202
LIST OF TABLES
Table 1-1.
Individual studies, investigators, affiliation, and current status of
science studies program for the NBY-89 ice core................................18
Table 2-1.
Ice core samples selected for the study of trace elements
time-series trends.................................................
Table 2-2.
.........
.......... 27
Ice core samples selected to locate a previously observed rare earth
elements enrichment peak around 89 meters depth...............................28
Table 2-3.
Ice core samples selected from volcanic eruption horizons....................28
Table 2-4.
Ice core samples selected for quality control purpose............................28
Table 2-5.
Elements scanned in ice core samples by INAA.................................. 38
Table 2-6.
Container bag-blank concentrations..................................39
Table 2-7.
Air-free ice production time chart........................................41
Table 3-1.
Concentration results for cross-profiling samples..............................
Table 3-2.
Median uncertainties on the concentrations of elements with
significant observation frequency...............................
46
...... 51
Table 3-3.
Periodicities and their power values in sea-salt sodium data set..............63
Table 3-4.
Average crustal Enrichment Factor results for potentially
crustal origin elements............................
Table 3-5.
........................ 68
The crustal Enrichment Factors of the enriched elements in
suspected volcanic eruption horizons................................
Table 3-6.
..... 83
Percent average concentration changes for Sb, As, Zn, and Cr
relative to the 1711-1901 time period................................................... 91
.... 96
Table 3-7.
Calculated natural background concentrations.......................
Table 3-8.
Factor analysis results for related parameters....................................... 100
Table 3-9.
Factor loadings (after varimax rotation) and estimated communalities ....105
Table 3-10.
Air-to-snow scavenging ratios for some elements............................... 113
Table 3-11.
Air content measurement results for samples and blanks.....................1...16
Table A-1.
Net elemental concentrations measured in individual NBY-89
ice core samples.................................................
..........
.......... 140
Table A-2.
Statistical summary information for the data in Table A- .................... 149
Table A-3.
Depth-age relationship for NBY-89 ice core..........................................152
Table A-4.
Net elemental concentrations calculated in annual intervals
for NBY-89 ice core........................................
Table A-5.
........
Most probable values calculated from elemental concentration
distribution functions .............................................
Table B-1.
................................................
173
Elemental concentrations for the samples obtained from
184
volcanic eruption horizons .............................
Table C-2.
Crustal Enrichment Factors for the samples obtained from
volcanic eruption horizons...................................
Table C-3.
........
185
Elemental concentrations for the samples obtained from a
REE anomaly horizon......................................
Table C-4.
164
Enrichment Factor calculation results with respect to marine
sodium...................................
Table C-1.
162
Enrichment Factor calculation results with respect to crustal
alum inum ........................................
Table B-2.
153
........
186
........
187
Crustal Enrichment Factors for the samples obtained from a
REE anomaly horizon......................................
1.
INTRODUCTION
1.1.
Background
A fuller understanding of the interaction between the land, ocean, and atmosphere
related processes has improved considerably within the last few decades (e.g., Charlson,
1987; Harriss et al., 1988; Budd, 1991; Schneider, 1994). At the same time, an awareness
of the impact of natural and anthropogenic substances on these systems has been
developed. For example, important clues regarding the influence of large scale volcanic
emissions on atmospheric albedo and, therefore, on short term climate variations were
recently obtained from various in-situ and satellite measurements (e.g., Handler, 1989;
Michelangeli et al., 1989).
Similarly, more substantial information is reported on the
impact of anthropogenic emissions, such as chlorofluorocarbon (CFC) compounds, and
their relation to changes within the atmosphere, by depleting stratospheric ozone (e.g.,
Molina and Molina, 1987; Toon et al., 1989; Molina, 1991). In addition, a number of
characteristic elemental signatures have been identified for aerosol source areas for
terrestrial and extraterrestrial materials (e.g., Phelan-Kotra et al., 1983; Lowanthal and
Rahn, 1985; Olmez and Gordon, 1985; Olmez et al., 1986; Olmez et al., 1988; Huang et
al., 1994).
Dynamic characteristics of environmental processes and the delicate balance
between the environment and anthropogenic activities creates a broad spectrum of
scientific, interdisciplinary research programs, which cover land, ocean, and atmosphere
related processes. However the lack of long-time observations is an important limiting
factor for the better characterization and formulation of these processes. The amassing of
surficial environmental data over long periods, except for temperature and perhaps
pressure and CO2, is quite recent. Reliable data with long collection histories are mostly
limited in space and duration. At the same time, determination of changes in atmospheric
composition over long time-units has become more important , especially as these changes
concern and are related to ecological and climatic changes as well as influencing life-
forms. Some examples are increasing acid rain formation, stratospheric ozone depletion,
greenhouse warming, and increasing toxic trace substances in the environment (e.g.,
Powers and Rambo, 1981; Lindqvist, 1985; Ramanathan, V., 1988; Abbatt and Molina,
1993).
A renewed interest has evolved in recent years to obtain historical data for
environmental parameters from specific sources, such as polar ice sheets, sediments, and
tropical sea corals, which preserve the information within their stratigraphic layers.
The Antarctic ice sheet has an average thickness of 2300 meters, with a maximum
known thickness close to 5000 meters. Two thirds of the land on which the ice sheet rests
is above sea level, mainly in East Antarctica, while most of the West Antarctic land is
below sea level (Walton, 1987).
The Antarctic and Arctic ice sheets contain a wide range of paleodata entrapped in
stratigraphic layers.
The layered sequences contain records of changing climatic
conditions and deposits of atmospheric constituents. These polar ice sheets are sinks for
atmospheric trace elements and other chemical species which were transported by wind
systems from various global sources (Wolff and Peel, 1985; Barrie, 1986; Shaw, 1989;
Davidson, 1989; Peel, 1989).
Recognizing this potential, a substantial number of
researchers have already obtained valuable concentration profiles of trace element and
other chemical species in several ice cores from polar locations (Langway et al., 1974;
Petit et al., 1981; Herron, 1982; Boutron and Patterson, 1983; Palais and Legrand, 1985;
Angelis et al., 1987; Saigne et al., 1987; Ivey and Davies, 1987; Boutron and Wolff, 1989;
Buat-Menard, 1990; Olmez et al., 1993).
The research presented in this thesis made on a polar ice core from the Antarctic
ice sheet was designed to measure the pre-industrial ( 18th and early 19t" centuries) and
modem era (late 19" and 20" century) annual average multi-element concentrations. The
core was meticulously studied by others and reliably dated by multi parameter crosscorrelation (Langway et al., 1994). The main scientific objective here was to assess the
impact of anthropogenic and natural processes on atmospheric elemental concentrations
and identify some of these sources. The study would result to further identify the overall
atmospheric elemental concentration budget of the Southern Hemisphere for both natural
and anthropogenic contributions and their probable sources
areas.
Although
anthropogenic impact on the environment is as old as humanity itself, the industrial
revolution starting in the early nineteenth century can be considered the beginning of large
scale contributions into the natural environment. As part of the study, snow strata that
covered 278 years (1711 AD to 1989 AD) was investigated to observe whether or not
there is a significant difference in the Antarctic ice sheet elemental concentrations due to
anthropogenic impact. In addition, included in this time-period were significant Earth
events, such as, volcanic emissions, variations in global air-mass movements, and changes
in Earth's vegetation cover, which might have had an effect on the elemental composition
of the atmosphere which could be investigated using trace element patterns.
Even though there have been previous research studies to determine the trace
element concentrations in polar ice sheets (e.g., Peel and Wolff, 1982; Boutron and
Patterson, 1983; Wolff and Peel, 1985; Boutron and Patterson, 1987; Girlach and
Boutron, 1992; Suttie and Wolff, 1992), most involved a relatively small number of trace
element measurements over discontinuous time-intervals. They were also limited by the
specific earlier analytical techniques used, the physical quality of the firn or ice core
samples used, and an evident lack of a close interdisciplinary and multiparameter approach
to an integrated study program. Of great importance, most of the previous data available
prior to this investigation does not reveal continuity over long time-periods. As stated
earlier, long records are necessary to provide an adequate understanding of the impact of
various emission sources on the atmosphere. Since changes in chemical composition
trends in the atmosphere are extremely slow, detecting these changes requires numerous
measurements and observations over an extended period of time. The results of this study
will hopefully fill an existing gap in our knowledge.
Although the expressions "ice core elemental concentrations" and "atmospheric
elemental concentrations" are used interchangeably here because of their relationship to
each other, this relationship is not straightforward by any means. This matter will be
discussed in section 3.4, which analyzes and explains the air-to-snow transport of aerosols
by various processes and mechanisms.
An auxiliary goal in this study was to develop a new method for determining the
air content in very small ice samples. A refined method to measure air content (and for
that matter argon by INAA) would be useful to study the relationship between the flow
patterns and air content changes of glacier ice with depth (as well as dating purposes). At
great depths in ice sheets (>1000 m), the thickness of an annual ice layer is often quite
small (generally <5 cm and less) due to plastic deformation and stretching of layers under
high pressure (Herron, 1982b). It is often difficult, if not impossible, to obtain seasonal
variations in parameters in these thin ice layers using the somewhat standard stratigraphic
dating parameters as discussed in section 1.4.
In addition, even if the seasonality of
stratigraphic dating parameters are detectable, analyzing tens of thousands of samples
from long ice cores are often not feasible. Under these circumstances, non-stratigraphic
dating methods, briefly mentioned in section 1.4, are desired for ice core dating.
Consequently a methodology was developed to measure air content within a few minutes
by direct ice phase irradiation and Argon gamma-ray spectrum analysis of 2 to 3 gram
samples.
1.2.
A Brief History of Antarctic Research
The development of Antarctic science is a perfect example of human courage and
curiosity to learn more about the unknown. In depth information about this development
can be found in the Antarctic literature (e.g., Walton, 1987; Fogg, 1992).
Fogg
suggested that the beginning of Antarctic science can be considered as early as 1699 when
Edmond Halley, a British geophysicist, sailed as far as 520 South in the Southern Ocean to
measure magnetic variation for determining longitude in open seas (Fogg, 1992).
However, the significant scientific expeditions in the continent started at the beginning of
the twentieth century. In the early years efforts were mainly in the form of surveying and
geological expeditions using dog sledges as the main transportation vehicles. The start of
aerial flights in 1928 opened a new chapter for these expeditions to map the continent.
Official collaboration between nations started with the first International Polar
Year of 1882-1883. A second Polar Year in 1932-1933 followed the first one. In 1951 a
special committee (Comit6 Special6 de l'Ann6e G6ophysique Internationale) was set up
for the coordination of international scientific efforts in polar regions. Its first meeting
(Paris, July 1955) was devoted mainly to deciding on the distribution of field stations and
coordinating scientific and logistic objectives (Walton, 1987). This cooperation between
nations resulted in many achievements in geology, geophysics, glaciology, biology, and
atmospheric sciences and still heralds a high potential for the future advancement of
international scientific endeavors.
The first ice core recovered in Antarctica was obtained during the NorwegianBritish-Swedish expedition of 1949-1952 on the Maudheim ice shelf. This nearly 100
meter-long ice core was drilled with modified rock drilling equipment (Fogg, 1992). In
1968 a U.S. team reached bedrock and recovered a 2164 meter-deep ice core at Byrd
Station in West Antarctica using a mechanical drilling rig, which is still the only ice core
that has completely penetrated the Antarctic Ice Sheet (Ueda and Garfield, 1969). In
addition, the U.S. teams drilled numerous other ice cores between 1956 and 1968. In
1972 a Soviet team started drilling a deep ice core at Vostok Station in East Antarctica,
which has a total ice sheet thickness of 3700 meters. A total of 2083 meters of core has
been recovered (Legrand et al., 1988b). At Vostok a thermal drilling technique (invented
by the Byrd'68 team) was used which relies on electrical heating of the corer annulus and
removing melted water quickly before refreezing. The glaciostatic pressure is balanced by
a mix of 224 trimethylpentane and diesel fuel (developed by Byrd'68 team) which has a
density close to that of ice and a lower freezing point than the surrounding temperature.
They also drilled another core at Komsomolskaya, which is 872 meters long, in 1983. A
joint US and French team drilled a 905 meter deep ice core near Dome C in 1977-1978.
In addition to the deeper ice cores mentioned, a number of shallow ice cores have been
obtained by a number of national teams from different locations. Figure 1.1. is a general
location map of ice coring sites.
1.3.
NBY-89 Ice Core Research Program
The NBY-89 ice core was augured in November 1989 by a three member team of
engineers from the Polar Ice Core Office (PICO) at the University of Alaska, with logistic
support from the U.S. Navy, at a location 1 km upstream from the temporary Byrd Station
Surface Camp (NBY-89, or Navy Byrd-89, the name designated by the U.S. Navy), West
5
90OW
o*E
SIce
Figure 1-1.
Map of Antarctica and major ice coring sites (from Palais and Legrand, 1985)
Antarctica (80' 01' S, 1190 31' W, 1530 m elevation) (Langway, 1992). The ice core is
164 m deep and 10 cm in diameter. Core recovery was continuous with over 99% of the
profile obtained. In addition, two 10 m-deep ice cores were augured about 14 km (NBY2) and 29 km (NBY-3) upstream from the main core. Two meter-deep pits were hand
dug at each drilling location. Four members from the Ice Core Laboratory, SUNY at
Buffalo, formed the science field team. The seven member science and drilling team spent
ten days at Byrd station and vicinity to accomplish these tasks (Langway, 1992).
Megascopic stratigraphic features, bulk density, and acidity (by Electric Conductivity
Measurement, ECM) of the core were measured continuously in the field.
A significant goal of this shallow ice core drilling operation was to investigate the
near surface layers, using contemporary state-of-the-art laboratory techniques to overlap
and extend to the surface the important environmental records obtained in the original
deep ice core drilling program in 1968 (Ueada and Garfield, 1969). All of the 1968 ice
core studies began 88.4 meters (reference horizon dated 1340 AD) below the 1968 snow
surface, where continuous core recovery first began, due to limitations in the then existing
drilling technology. As a result, more than 500 years of ice core chronology (top 88.4 m)
from the 1989 A.D. surface at Byrd Station was not available for study prior to the
undertaking of this project.
The full research program for the NBY-89 ice core include the laboratory
measurement and analysis of variety of physical and chemical properties performed by
several research groups as listed in Table 1.1. The age of the ice core at the bottom was
determined to be 1360 years (Langway et al., 1994).
correlating the ECM,
8180,
Dating was done by cross-
and ionic chemistry stratigraphic records and with well
recognized reference horizons of volcanic origin and cross-checked with the density
profile and a total
f3 curve for the upper firn layers. The overall dating accuracy is
estimated as better than ±2 years.
Table 1.1
Individual studies, investigators, affiliation, and current status of science
studies program for the NBY-89 ice core (Updated from Langway, 1992). I
Institute
Investigator(s)
Study
Samplinga
Status
State
University
of
New
York at Buffalo
C.C.
Lang
way,
Jr.,
Physical
stratigraphy
C
Finished
H. Shoji, and
co-workers
Structure
Physical properties
Mechanical properties
I
C, I
I
Finished
Finished
In progress
C.C. Langway, Jr.,
K. Osada, and
co-workers
Chemical stratigraphy
Volcanic Layers
Ionic concentration levels
Organic chemistry
Embedded solids
C, I
I
C, I
Finished
Finished
Finished
In progress
In progress
University of
Copenhagen
H. Clausen,
C. Hammer,
C.C. Langway, Jr.,
and co-workers
Acidity
Oxygen isotopes
$-activity levels
Dust
University of Colorado
W. Dansgaard,
S. Johnsen, and
J. White
Deuterium
University of Bern
H. Oeschger
I
I
Finished
Finished
Finished
In progress
C. I
In progress
Carbon dioxide, methane,
and nitrous oxide
I
In progress
A. Neftal
Hydrogen peroxide,
I
Finished
B. Stauffer
Beryllium-10
I
In progress
U. Stigenthaler,
C.C. Langway, Jr.,
and co-workers
Carbon- 13/carbon- 12
I
In progress
University of Rhode
Island
M. Bender
and co-workers
Oxygen, argon, and
nitrogen isotopes in gas
phase
I
In progress
Massachusetts Institute
of Technology
I. Olmez,
C.C. Langway, Jr.,
and co-workers
Time-series trends of trace
elements (THIS WORK)
A new method for air
content measurement
' C denotes continuous; I denotes intermittent
C, I
Finished
I
Finished
1.4.
Scope of Research
The Antarctic continent covers approximately 10% of the Earth's land surface with
almost 99% of the continent permanently covered by snow and ice. Consequently, the
predominant sources for the natural aerosol particles found in the ice are not of local
origin but the result of long-range transport of aerosol and particulate matter from distant
continental and oceanic areas of the globe. Transport is accomplished via upper and
middle-troposphere trajectories with active gas to particle conversion reactions occurring
during particle transport (Dick, 1991). The anthropogenic impact in Antarctica is minimal
due to its distance from population centers. The long-range transport and relatively slow
vertical mixing in the Antarctic atmosphere results in a homogeneous and size-segregated
aerosol input to the Antarctic region (Cunningham and Zoller, 1981).
Snow accumulates at high-elevation polar regions in a layered structure without
melting due to the low temperatures throughout the year. In the higher elevation regions
of Antarctica snow accumulation exceeds ablational processes and it is possible to observe
seasonal variations in augered ice cores.
One of the most powerful parameters used in dating polar ice cores is the oxygen
isotope ratio but seasonal cycles are much more difficult to determine in Antarctica than
Greenland. This method was first introduced into glaciology by Dansgaard (1954). The
seasonal change of isotope ratios in precipitation is strongly related to the temperature
during the condensation. The ratio of oxygen-18 and oxygen-16 isotopes in precipitation
is larger during the summer season than the winter season due to higher temperatures
during the summer precipitation (vapor pressure of H2160 is approximately 1 % higher
than that of H2180 (Jouzel and Merlivat, 1984). The isotopic composition is measured by
mass spectrometry and traditionally is expressed by the 8 function (Hammer, 1989) as,
8180 = [ (Rs-RsMow)/RsMow ]x1000 %c
(1.1)
where Rs and RsMow are the isotopic ratios of oxygen-18 and oxygen-16 in the sample and
in standard mean ocean water, respectively. In a similar way hydrogen isotopes can also
be used for dating purposes. In older ice, the diffusion process distorts the seasonality of
the signal (Johnsen, 1977) and presents a difficulty in Antarctic cores. The temperature
dependence of the oxygen and hydrogen isotopes can also be used to obtain past
atmospheric temperatures. However, this relationship is not as straightforward due to the
fact that the amount of original water vapor remaining in the air mass is determined by the
complicated air mass mixing effects during transportation to the ice sheets (Charles et. al.,
1994). These mixing effects include the location of the original moisture source, the
trajectories of the moisture, and the mixing between sources with different isotope
distillation levels.
Another useful measuring parameter with a seasonal relationship in ice cores is the
ECM technique (Electric Conductivity Measurement) (Hammer, 1983). This technique
relies on the determination of acidity levels via direct electric conductivity measurements
on frozen ice cores. The acidity contained in the deposited ice layers is mainly the result
of precipitation on to the ice sheets of gas-derived atmospheric acids, mainly H250 4 and
HNO 3. The increasing sulfate concentration levels in spring and summer snow deposits
are thought to be the result of: photochemical formation of excess sulfate from its organic
gaseous precursors (Legrand and Delmas, 1984), sea water, or volcanic sources. The
origin of nitrate in polar precipitation is still controversial (Delmas and Legrand, 1989) but
lightening was suggested as a possible source (Kley, 1983). The ECM method is fast and
easy (with competent ice cores), with high resolution as long as the precipitation is acidic
enough with a modest annual deposition rate and the seasonal signal is not distorted by
possible conflicting seasonal trends of different acids or by volcanic origin acidic species
(Hammer, 1989).
Another method for ice core dating that shows regular seasonal dependence is
microparticle concentration measurements. Since during the austral summer season the
crustal aerosol production is higher and aerosol removal by precipitation is lower, there is
an increasing aerosol transport into Antarctica mainly from the continental areas of the
Southern Hemisphere (Tuncel et al., 1989). The most commonly applied technique for the
measurements is the use of a Coulter microparticle counter.
This technique has the
advantage of in situ applicability but time consuming and subject to complicated
interpretation of the results.
Applications of the method have been made on both
Greenland and Antarctic ice cores (Thompson, 1977; Hammer et. al., 1985).
Some chemical species also show seasonal dependence, and thus can be used for
stratigraphic dating purposes. S042-, N0 3-, and H20 2 are some examples. The degree of
seasonality for any one of these species might vary with the site and time interval covered
(Hammer, 1989).
The seasonality of these species has been demonstrated both in
Greenland and Antarctica (Langway et. al., 1977; Herron, 1982; Neftel et. al., 1984;
Langway et. al., 1994) and have been shown to be an invaluable chemistry index marker
for historically recorded volcanic eruptions (e.g., Tambora, Krakatau, Katmai).
Any one of these parameters might show a strong or a weak seasonal signal for
stratigraphic dating purposes, depending upon the location and period of deposition.
Therefore, the best overall method for accurate dating is to use all of these methods on an
ice core and cross-correlate the results. For example, in an exceptional and unique study,
the estimated standard deviation for continuous dating of the 0 to 980 meters depth
interval (1979 A.D - 625 B.C.) in Dye 3, Greenland deep ice core has been reported as ±5
years at the bottom by cross-correlating the results of oxygen isotopes, acidity, and
microparticle measurement (Hammer et. al., 1986).
In addition to these detailed and reliable stratigraphic dating methods, some other
less accurate, but sometimes crucial, methods are also used for specific purposes.
Although no in depth information about these methods will be given here, it might be
useful to mention the basic principles.
One of these methods that is always used for checking the accuracy of
stratigraphic dating is called the "Reference Horizons" method and relies on the signatures
of known global or regional scale events, such as volcanic eruptions and atmospheric
nuclear bomb tests, on the polar ice sheets in a specific year.
Two other independent, non-stratigraphic methods use naturally produced
radioactive isotopes and ice flow phenomena as ice core dating parameters.
These
methods are especially useful for dating deep ice cores that have either thin annual layers
due to plastic deformation, and, hence, whose seasonal signals are not clear enough for
stratigraphic dating, or that have lost stratigraphy due to bed-rock scouring of their deep
layers. In addition to their usefulness under these specific conditions, these methods might
also be preferable where continuous stratigraphic analysis is not done or the ice core is not
continuous. In the first method natural radioactive isotopes enclosed in ice as part of the
water substance (3H), in form of aerosols (e.g., 32Si, 1'Be), or in the air bubbles (e.g., 39Ar,
14C, 81Kr) are used for dating (Stauffer, 1989). The latter of these
methods combines ice
flow modeling with the air content-sample depth relationship to date the deep ice layers.
This method relies on the fact that the amount of air scavenged in the ice layers is
proportional to the density of air (a function of pressure and temperature), and therefore,
the elevation at the time of pore close-off, which is the complete isolation of air bubbles
from the surrounding atmosphere (Langway, 1958; 1970; Shoji and Langway, Jr., 1989).
Thus, the original elevation of a specific sample can be found by air content measurement
(assuming the temperature history is known), and the total distance traveled by that
sample through ice flow is calculated from the elevation difference and the slope of the ice
sheet. Although the relationship between the air content and elevation might change due
to the possible long-term modifications of atmospheric circulation patterns over the ice
sheets, so the atmospheric pressure-elevation relationship (Martinerie et al., 1992), the
scales of these changes are difficult to predict and ignored in the calculations. In addition,
possible variation of pore volume per unit ice mass at the time of pore close-off also
affects the relationship between the air content and elevation.
It was shown that, this
variation is mainly due to the temperature dependence of this parameter, and should be
treated if the temperature data (from oxygen and/or deuterium isotopes analysis) is
available for more accurate results (Raynaud and Lebel, 1979). Flow velocities of specific
ice layers can be calculated from mathematical models, which employ physics laws and
topographical information. In addition, these models can be verified by experimental borehole measurements on the ice flow trajectory (e.g., Russell-Head and Budd, 1979), and to
certain extent by the satellite measurements on surface layer movement (e.g., Goldstein et
al., 1993; Fahnestock et al., 1993). Finally, the sample age is calculated from the travel
distance and velocity profile.
1.5.
Basic Theory of the Instrumental Neutron Activation Analysis
The Instrumental Neutron Activation Analysis (INAA) is a non-destructive multielement measurement technique that relies on the neutron capture and subsequent gammaray emissions of atomic nuclei. The following is a brief review of the basic theory. The
historical development, applications, and in depth theory can be found in the extensive
literature (e.g., Olmez, 1989; Knoll, 1989; Alfassi, 1990).
When target nuclei in a sample are bombarded (irradiated) by low energy thermal
neutrons, some of the nuclei are transformed into a metastable state by capturing the
incoming neutrons. The main source of the thermal neutrons used for the irradiations of
samples are nuclear research reactors that are specifically designed for high neutron flux
output. The half-life of a nucleus in this excited state is very short (< 101 2 s) and it decays
to a lower state by emitting "prompt" gamma-rays that can also be used for trace elements
analysis by another technique (prompt gamma activation analysis). Following this (n, y)
reaction, the radioactive nucleus will often further decay by electron emission, electron
capture, or positron emission, and the resulting "daughter" nucleus will emit "delayed"
gamma-rays. These are the gamma-rays used in instrumental neutron activation analysis.
The case of an (n, y) reaction followed by positron decay is illustrated schematically in
Figure 1.2.
(X+n)*
Prompt y's (PGAA)
..
+n .
Delayed y's (INAA)
"'*f
AX
X
A+lI
A+ 1
zX
Figure 1.2. Illustration of (n,y) reaction followed by
Z
f3
X
decay.
A calculation of the amount of activity induced in a sample at the end of the
irradiation can be made using the following formula:
Ag = 4oN(1-e
- kt i )
(1.2)
where,
Ao : Activity at the end of the irradiation
0 : Flux [neutrons/cm 2-s]
a : Neutron capture cross-section, in barns [barn= 10-24 cm2]
X: Decay constant [In 2/t112]
tl/2 : half-life
N : Number of target nuclei in sample [nuclei/cm 3]
ti: irradiation time
In general there will be some delay between the end of irradiation and beginning of
gamma-ray spectrum collection, and this time is called the "cooling time" (t,). Activity at
the end of the cooling time will be (A=Ao e- Xtc ), and it is related to the gamma-ray
spectrum peak area (interference and background corrected) by the following equation:
A = Ao e- tC =
P
(1- td)(1-e
-
(1.3)
s)
where,
A : Activity at the end of the cooling time
P : Measured net gamma-ray spectrum peak area
ts: Spectrum collection time
td
: Fractional "dead-time"
Here, the "dead-time" correction is made to account for the time that analyzer is
not active due to signal processing limitations. To calculate the absolute elemental
concentrations from this equation, the efficiency of the detector should be known. There
are however some drawbacks in using this direct calculation method.
One is the
dependence of detector efficiency on the counting geometry, and the other is the
possibility of neutron flux change during the irradiation. To eliminate these uncertainties,
a comparative method can be employed as in the case of this work. In this method, a
standard material with an accurately known composition is irradiated along with the
sample. The unknown weight of an element of interest in a sample can be found from the
following relationship:
Wsample
-
Asample
Ws tandard
As
Astandard
where,
Wsample : Weight of element in sample
Wstandard : Weight of element in standard
Asample : Activity of sample at the end of irradiation
Astandard : Activity of standard at the end of irradiation
(1.4)
2.
EXPERIMENTAL
2.1.
Sample Selection and Preparation
2.1.1. Selection
A total of 97 individual ice core samples were selected and measured by
instrumental neutron activation analysis (INAA) to accomplish the main part of this study
(Table 2.1). The samples cover both pre-industrial (< 1815 A.D.) and industrial timeperiods. Continuous sampling was done for the first 15 meters depth, which extends over
the time-period between 1926 AD and 1989 AD. There are sixty-nine samples covering
this time period. In addition, selective interval sampling was done between the 15 meter
and 42 meter depths, which covered the overall time period from 1711 A.D. to 1926 A.D.,
to obtain background information. Twenty-eight samples, each covering approximately a
one year time-interval for a 6 to 12 year continuous record, were obtained over this timeperiod.
An additional 20 samples were carefully selected to measure specific episodic
events, identified by other investigators working on this core (Langway and Osada,
personal communication), and from a previous study (Keskin et al., 1992). Among these,
a group of 12 samples (Table 2.2) were selected from the depth interval between 88.15 to
89.51 meter depths to locate the peak position of a previously observed (Keskin et al.,
1992) rare earth elements enrichment around the 89 meter depth. Another group of 8
samples (Table 2.3) was selected from certain years that either directly coincide with
historically known volcanic eruptions or show high sulfur concentrations (Langway and
Osada, personal communication) as an indicator of volcanic eruptions. Additional 3 pairs
of samples were selected from the time-period of 1711 AD to 1989 AD for quality control
purposes (Table 2.4).
Table 2-1. Ice core samples selected for the study of trace elements time-series trends.
Sample
No
Sample
ID
1IC1
1IC2
1IC3
2IC1
2IC2
2IC3
3IC1
3IC2
3IC3
3IC4
4IC1
4IC2
4IC3
4IC4
5IC1
5IC2
5IC3
5IC4
5IC5
6IC1
6IC2
6IC3
6IC4
6IC5
7IC1
7IC2
7IC3
7IC4
7IC5
8IC1
8IC2
8IC3
8IC4
8IC5
9IC1
9IC2
9IC3
9IC4
9IC5
10IC1
10IC2
10IC3
10IC4
10IC5
11IC1
11IC2
11IC3
11IC4
11IC5
Approximate
Depth
Interval [m] Date [A.D.]
1989
0.00-0.33
0.33-0.66
0.66-1.00
1.00-1.33
1.33-1.66
1.66-2.00
2.00-2.25
2.25-2.50
2.50-2.75
2.75-3.00
3.00-3.25
3.25-3.50
3.50-3.75
3.75-4.00
4.00-4.20
4.20-4.40
4.40-4.60
4.60-4.80
4.80-5.00
5.00-5.20
5.20-5.40
5.40-5.60
5.60-5.80
5.80-6.00
6.00-6.20
6.20-6.40
6.40-6.60
6.60-6.80
6.80-7.00
7.00-7.20
7.20-7.40
7.40-7.60
7.60-7.80
7.80-8.00
8.00-8.20
8.20-8.40
8.40-8.60
8.60-8.80
8.80-9.00
9.00-9.20
9.20-9.40
9.40-9.60
9.60-9.80
9.80-10.00
10.00-10.20
10.20-10.40
10.40-10.60
10.60-10.80
10.80-11.00
1989
1989
1988
1988
1987
1986
1986-85
1985-84
1984
1984
1984-83
1982
1982
1981
1980
1980-79
1979-78
1978
1977
1976
1976-75
1975
1974
1973
1972
1972-71
1970
1969
1969
1968
1967
1966
1966-65
1964
1963
1962-61
1960
1959
1958
1958-57
1956
1955
1954
1954-53
1952
1951
1950
1950-49
Sample
No
Sample
ID
12IC1
12IC2
12IC3
12IC4
12IC5
13IC1
13IC2
131C3
13IC4
13IC5
14IC1
14IC2
14IC3
14IC4
14IC5
15IC1
15IC2
15IC3
15IC4
15IC5
16IC1
17IC1
18IC1
19IC1
20IC1
21IC1
22IC1
23IC1
241C1
25IC1
26IC1
27IC1
28IC1
29IC1
30IC1
31IC1
32IC1
33IC1
34IC1
35IC1
36IC1
37IC1
38IC1
39IC1
40IC1
41IC1
42IC1
431C1
Depth
Approximate
Interval [m] Date [A.D.]
11.00-11.20
1948
11.20-11.40
1947-46
11.40-11.60
1946-45
11.60-11.80
1945-44
11.80-12.00
1944-43
12.00-12.20
1942-41
12.20-12.40
1941
12.40-12.60
1941-40
12.60-12.80
1940-39
12.80-13.00
1939-38
13.00-13.20
1938-37
13.20-13.40
1937-36
13.40-13.60
1936-35
13.60-13.80
1935-34
13.80-14.00
1934-33
14.00-14.20
1933-32
14.20-14.40
1931-30
14.40-14.60
1930-29
14.60-14.80
1929-28
14.80-15.00
1927-26
15.00-15.17
1926-25
16.00-16.17
1919-18
17.00-17.17
1913-12
18.00-18.17
1907-06
19.00-19.17
1901-00
20.00-20.17
1895-94
21.00-21.17
1889-88
22.00-22.16
1881-80
23.00-23.16
1870-69
24.00-24.16
1858-57
25.00-25.16
1846-45
26.00-26.15
1837-36
27.00-27.15
1830-29
28.00-28.15
1822-21
29.00-29.15
1815-14
30.00-30.15
1807-06
31.00-31.15
1799-98
32.00-32.14
1791-90
33.00-33.14
1782-81
34.00-34.14
1773-72
35.00-35.14
1766-65
36.00-36.14
1759-58
37.00-37.14
1752-51
38.00-38.14
1744-43
39.00-39.14
1736-35
40.00-40.14
1728-27
41.00-41.14
1720-19
42.00-42.14
1711-10
Table 2-2. Ice core samples selected to locate a previously observed
Rare Earth Elements enrichment peak around 89 meters depth.
Sample
No
Sample
ID
Depth
Interval [m]
Approximate
Date [A.D.]
1
2
3
4
5
6
7
8
9
10
11
12
89LC1
89LC2
89LC3
89LC4
89LC5
89LC6
89LC7
89LC8
90LC1
90LC2
90LC3
90LC4
88.15-88.26
88.26-88.37
88.37-88.48
88.48-88.59
88.59-88.70
88.70-88.81
88.81-88.92
88.92-89.02
89.02-89.14
89.14-89.26
89.26-89.38
89.38-89.51
1341
1341
1340
1339
1338
1338
1337
1336
1335
1334
1333
1332
Table 2-3. Ice core samples selected from volcanic eruption horizons.
Sample
No
Sample
ID
Depth
Interval [m]
Approximate
Date [A.D.]
1
2
3
4
5
6
7
8
22V1
22V2
22V3
22V4
29V1
29V2
51V1
51V2
21.38-21.53
21.53-21.70
21.70-21.85
21.85-22.00
28.15-28.28
28.28-28.40
50.02-50.17
50.17-50.32
1887-86
1885-84
1884-83
1883-82
1821-20
1820-19
1647-46
1646-45
Table 2-4. Ice core samples selected for quality control purpose.
Sample
No
Sample
ID
Depth
Interval [m]
Approximate
Date [A.D.]
1
2
3
4
5
6
17CP1
17CP2
23CP1
23CP2
28CP1
28CP2
16.75-17.00
16.75-17.00
22.75-23.00
22.75-23.00
27.17-27.42
27.17-27.42
1915-14
1915-14
1869-68
1869-68
1829-28
1829-28
2.1.2. Preparation
After the field drilling operation in 1989, the NBY-89 ice cores were transported
and stored at the Ice Core Laboratory (ICL) at SUNY, Buffalo. Each 1 meter ice core
section was placed in a polyethylene bag and kept in a protective capped tubing. These
tubes were stored on shelves in a cold room at -28 C'.
Prior to the chemistry preparation sampling process, all the necessary tools for
core surface cleaning, such as pure nickel plates and polyethylene bags, were pre-cleaned
at the Environmental Research & Radiochemistry (ER&R) Division Laboratory at
Massachusetts Institute of Technology Nuclear Reactor Laboratory (MIT-NRL). A 99.5
% pure-Ni metal plate was used to surface clean the outer layer of each sample to remove
possible surface contaminants induced during the field core drilling and handling. The
plates (10x12x0.079 cm) were thoroughly cleaned with methanol, rinsed with deionized
(DI) water, and stored in acid cleaned polyethylene bags prior to use. Nickel is one of the
elements to which instrumental neutron activation analysis (INAA) is not very sensitive,
and its hardness is proper to shave solid ice surfaces.
The polyethylene zip-lock ice storage bags were soaked inside and out with 25 %
nitric acid by volume for 36 hours. They were rinsed four times with DI water and dried
in a clean bench after turning them inside out again. Laboratory grade Mallinckrodtfm
brand nitric acid was used for cleaning processes. The DI water for dilution and rinsing
bags was produced by a ComingMT LD-5 system with Bamstead TM MEGA-PURE® high
purity cartridges (resistivity > 2MG).
After preparation, the necessary equipment was transported to ICL at SUNY,
Buffalo. The core sampling process was completed in three separate trips. After the
removal of each ice core tube from the inner cold room (-28 Co) to the sample preparation
room (-23 Co), the core was removed from its container and samples from pre-determined
depths were cut with a band saw. Each sample weighed 150 to 200 grams before surface
cleaning (portions of the core segments from the same depth remain untouched and are
available for possible use in other research projects). After the cutting step, each sample
was placed horizontally in a clamp on a clean bench and its surface shaved with the clean
nickel plate.
Shaving was done by layers all around the sample surface, removing an
approximately 6 to 10 mm thick layer. The clean inner part was enclosed in an acid
cleaned polyethylene bag.
Holding this bag and the contained ice sample firmly, the
sample was separated from the clamped section by creating a weak point with the nickel
plate and bending it to break off. This way, the surface of the shaved ice samples was not
touched by any material except the acid cleaned bags. The remaining section of each
sample within the clamp was discarded. A simple schematic of this stage is given in Figure
2.1.
Weak
point
<
> Clamp
Bending
lll noiteid
-
....... > Shaved ice
Polyethylene <
block
bai
Figure 2-1. Schematic illustration of ice sample surface cleaning setup.
After closing the zip-lock, the sample was placed into another zip-lock bag (a label card
was placed in this second bag) and stored in a freezer in the cold room. The net sample
weights after the surface cleaning process were 60 to 100 grams each. During the sample
cleaning process polyethylene gloves, protective clothing, and masks were used to prevent
any possible contamination to the samples.
2.1.3. Pre-concentration by Freeze-drying
The majority of the elemental concentrations in Antarctic ice samples are at
nanogram and sub-nanogram levels (Batifol et al., 1989; Gbrlach and Boutron, 1992).
These low concentration levels require the use of over 50 gram of ice for each sample.
This is necessary to substantially exceed the INAA detection limits of most of the elements
for accurate concentration measurements. However, there are limitations on the volume
of a sample that can be irradiated and counted without some artifacts.
The INAA
technique is best suited for solid samples in small volumes. Small volumes prevent the
neutron self-shielding effect in the inner region of sample matrix, and solid samples
simplify and speed up the handling phase. A second limitation is the difficulty involved
during gamma-spectrum collection of radioactive samples. Sample counting geometry is
an important factor for detector collection efficiency, which in turn directly affects the
measurement errors due to counting statistics.
In addition, sample self-shielding of
gamma-rays in large volumes and contamination problems related to liquid samples are
unwanted features for large volume liquid sample analysis.
Two volume reduction techniques are applicable to ice samples: freeze-drying ice
samples in the solid state, and evaporation of melted ice samples in liquid state. Each
technique has advantages and disadvantages. Evaporation of melted ice is substantially
faster than freeze-drying. However, one problem of evaporation is the possibility of loss
of some elements by volatilization (Tanizaki, 1990).
Although for a very slow, low
temperature, non-boiling evaporation process this loss may be prevented (G6rlach and
Boutron, 1990), the prevention of loss of volatile species and contamination from the
surrounding environment throughout the long evaporation time is a difficult task. For
freeze-drying, the major drawbacks are the slow turnaround time and possible loss of
elements with high vapor pressure. However, slow separation of water molecules from
only the frozen surface layer makes it less likely that some elements will be carried out of
the sample container.
In addition, the closed, under-vacuum surrounding prevents
external contamination. It has been shown previously (Harrison, 1977) that as a result of
the freeze-drying process of water samples with known amounts of radioactive elemental
tracers, all but two (Hg and I) out of 22 elements studied showed retention yields of 96 %
to 100 %. Considering that there are only a few elements that can be lost significantly due
to their high vapor pressure (Hg, I, and Cl), freeze-drying was used here as the sample
pre-concentration technique. The basic principle of this technique is separation of ice and
the residue it contains by sublimating the ice under vacuum. To prevent the sublimating
water vapor from going into the vacuum line and to produce humidity free chamber, a
cooled coil (- 55
oC)
is used to condense it. A simple schematic diagram of the freeze-
drying system is Figure 2.2.
The low elemental concentration levels in the ice samples require the contribution
from the sample containers of the freeze-dried samples to be minimal. Although it would
be possible to freeze-dry each 50 to 80 grams of ice without transferring it from its
original polyethylene bag, the contribution of each element from the container material
itself would be high compared to the net concentration levels expected in ice residue. To
overcome this problem, small (approximately 100 milligram), thin-wall polyethylene bags
were used as sample containers during freeze-drying (bag selection and characterization
steps are explained in detail in section 2.2.3). It was possible to freeze-dry 4 to 6 grams of
ice at a time using a multi-step freeze-drying process.
....> Vacuum
chamber
'QUUU'
:
,>
Condenser
coil
.> Vacuum
pump
Ice
sample
Dlug
Figure 2-2. Schematic illustration of the freeze-drying system.
The polyethylene sample container bags and transparent polypropylene vials (0 35
mmx60 mm), used as rigid holders for container bags, were acid cleaned in the same way
ice storage bags were cleaned as explained previously. They were dried in a clean bench
on clean analytical grade washed filter papers (S&S
M
T
, # 589). After they were dried, the
holders and bags inside them were placed into clean, closed, glass vacuum desiccators.
Before closing the cover of each desiccator, clean analytical grade filter papers were
placed on top of the holder vials to prevent any possible contamination during closing and
opening of the desiccator cover.
Since the freeze-drying capacity of the system (LABCONCO , Model 75200) is
limited to a certain amount of ice mass, 30 individual sample containers could be
processed in one or more vacuum desiccators at a time, which meant approximately 150
grams of total ice mass. This limitation is due to the need for holding a high enough
vacuum level inside the vacuum chamber and, thus, each desiccator, to prevent the melting
of ice, which essentially stayed at room temperature. Melting would cause the suction of
partially frozen samples out of the container bags, which would result in the loss of
elements from the containers. For our research sample preparation and 15 consecutive
stage freeze-drying cycles (six group of 30 samples, including empty control bags) were
completed in over a one and a half year period.
2.2.
Instrumental Neutron Activation Analysis
2.2.1. Irradiations
At the end of the fifteen consecutive freeze-drying steps, each desiccator was
taken onto a clean-bench, and each sample bag was heat-sealed to prevent any loss of
residue during the sample irradiations. After heat-sealing, each bag was folded three times
on an analytical grade washed filter paper, in a way to minimize the sample size and shape
variations to assure a constant geometry during counting. After the folding, each bag was
placed into another acid-cleaned polyethylene bag, heat-sealed, and labeled. The same
steps were repeated for empty bags, which were used as blank control samples. During
these sample preparation steps, standard clean-room procedures were followed.
Since comparative INAA was being used as the measurement technique, NIST
certified standard reference materials were used as standard samples in the analysis. The
standard and control samples were "Coal Fly Ash - 1633a" and "Orchard Leaves - 1571",
respectively. For short (10 minutes) irradiations one 5 to 6 mg standard sample and one 8
to 9 mg control sample was used for each detector. To prevent excessive Na-24 isotope
production, and therefore high background noise, these standard and control sample
weights were reduced for long (24 hours) irradiations, and two 2-3 mg standard samples
and one 5-6 mg control sample was used for each detector.
The same clean room
procedures were followed during the preparation of the reference material samples.
In the short irradiation process, elements with radioactive isotopes with half-lives
between a few minutes to a few hours were determined. For this group of elements, 10
minute irradiation duration was determined as an optimum time in the 8x10 12 n/cm 2-sec
thermal neutron flux. Irradiations were done by inserting four samples inside a sample
carrier (rabbit), and sending the container to the reactor irradiation location from the
radioactive sample handling room by an automatic pneumatic transfer system. In general,
there are two considerations for the number of samples to be irradiated at one time for
short periods. The first is the number of high resolution gamma-ray detectors available for
use, and the second is the time necessary to prepare the samples for counting at the end of
irradiations, which should be kept minimal not to allow very short-lived elements to decay
before counting. After 10 minutes irradiation, the samples were allowed to decay for one
minute. The purpose of this was to reduce the working dose by letting some very shortlived (on the order of seconds) elements (mainly fluorine) to decay, since they can not be
determined at trace concentrations anyway, due to the comparatively long sample
packaging and transfer time required before the gamma-ray spectrum collections. After
receiving each irradiation container from the reactor through the pneumatic system, the
dose equivalent value at 30 cm was measured by a Geiger counter in the radioactive
sample handling laboratory. If this value was over five mrem/hr, it has been cooled until
the level fell below this value, and then samples were removed with long tweezers onto a
radioactive sample preparation hood, which is shielded for worker radiation protection.
Each outer sample bag was cut open with scissors and the inner sample bag was placed
into a clean, non-radioactive bag using separate clean TeflonTM tweezers. After finishing
the sample packaging step, the four samples were quickly transferred to the sample
counting room in a lead container. The same steps were followed for standard and control
samples.
After an average decay period of one week, the previously irradiated samples (10
minutes for short-lived element determination) were placed into an irradiation container
for longer irradiation. Irradiation duration of 24 hours was chosen as optimum in the 8x
1012 n/cm 2-sec thermal neutron flux. A maximum of eight samples per detector (total of
32) can be irradiated at a time to allow for the counting of samples before a considerable
level of decay. In addition, a total of eight standard samples and four control samples
were placed into each container for four detectors. At the end of each irradiation, samples
were allowed to decay two to three days to reduce the activity from some highly abundant
and comparatively short-lived (of the order of hours) elements (mainly sodium) and
prevent detector saturation and high background values during the gamma-ray spectrum
collection.
After this decay period, samples were packaged as explained above and
transferred to the counting laboratory in lead containers.
2.2.2. Gamma-Ray Spectroscopy
The gamma rays emitted from the radioisotopes were counted using high
resolution HPGe detectors coupled with an 8192-channel pulse-height analyzer; spectra
were analyzed using computer-directed programs.
As explained in the previous section, irradiation durations, cooling and spectrum
collection times required optimizing depending upon the sample matrix and elements of
interest. Gamma-ray spectrums of each sample were collected in four stages, two after
the short irradiation and two after the long irradiation. At each stage, certain elements
with similar half-lives were determined. The counting duration was chosen not to be
longer than three half-lives of the shortest-lived element within a group of elements that
will be determined in a particular stage.
After each short-period irradiation (10 minutes), four samples were transferred to
the Counting Laboratory. After the transfer, each sample was placed on top of a detector
at 7 cm distance. Sample-detector distance was chosen so that at least ninety percent of
the time detector would be collecting gamma-rays emitted by the sample. In other words,
detector "dead time" would not exceed ten percent of the real counting time. The
occurrence of "dead time" is due to the coupled detector analog-digital conversion
electronic circuitry requirement of a certain time period to process an incident gamma-ray
from a radioactive isotope. During this signal processing step of an incident gamma-ray,
the detector is blocked electronically from other incident gamma-rays. The selection of
under ten percent "dead time" was made to minimize the spectral distortions.
The first stage (shorts-1) of counting was done for the net counting period of six
minutes and forty seconds. Following this, the second stage (Shorts-2) of counting was
done right after finishing the first stage for the net counting period of thirty minutes with
the same counting geometry. In these counting stages elements given in Table 2.5 were
scanned for concentration determination. Figure 2.3 shows a representative gamma-ray
spectrum for short lived (shorts-1) elements.
Gamma-ray spectrum collections following each long-period irradiation (24 hours)
were done in two stages. Since activity of the samples were low enough not to cause high
"dead time" values, each sample was placed right on top of detector to improve counting
efficiency. The first stage (Longs-1) of countings were done two to three days after the
irradiations with the counting periods of around six hours. The second stage (Longs-2)
countings were done two to three weeks after the first ones to let the medium half-lived
isotopes to decay extensively, so decrease the background and interferences for the second
stage elements. The counting periods were around twelve hours with the same sample
position as the previous stage. The elements scanned for concentration determination
during these counting stages are also given in Table 2.5.
After these collection stages, each spectrum was checked on the computer screen
for possible interferences on some of the peaks that were used by the computer program
8Z-IV
-
..
8S-1J
-
ZS-A
OO
i l I
LWW
vo acu
U.. m
ID
4a
LLOUf
9S-UN
I-r!I
for the determination of element concentrations.
Interactive peak fitting was performed
on each low intensity gamma-ray peak and portions of the spectra, wherever the detector
resolution would not be enough to separate peak doublets.
After these final checks,
elemental concentrations were calculated by the computer program and printed out as
hard copies.
Table 2-5. Elements scanned in ice core samples by INAA.
Element Half-life Key Energy Scanning Element Half-life Key Energy Scanning
[keV]
Stage
[kevy]
Stage
Al
2.25 m
1779.0
Short-i
Te
1.35 d
149.8
Long-1
Cu
5.10 m
1039.3
"
W
0.996 d
479.6
Mg
9.45 m
843.8
"
U
2.36 d
106.4
Ti
5.76 m
320.1
"
Yb
4.19 d
396.3
V
3.76 m
1434.1
"
Ce
0.089 y
145.4
Long-2
Ba
1.396 h
165.9
Short-2
Cs
2.065 y
795.9
Cl*
0.62 h
1642.4
"
Cr
0.076 y
320.1
"
Dy
2.33 h
94.7
"
Co
5.271 y
1173.2
Ga
14.1 h
834.1
"
Eu
13.48 y
1408.0
In
0.903 h
417.0
"
Gd
0.662 y
97.4
I
0.417 h
442.9
"
Hf
0.116 y
482.1
Ir
0.202 y
316.5
2.578 h
846.8
"
Mn
Na**
14.96 h
1368.6
"
Fe
0.122 y
1099.2
208.4
388.4
"
Lu
0.018 y
Sr
0.291 h
Sb
2.70 d
564.1
Long-1
Nd
0.03 y
91.1
It
Rb
0.051 y
1076.7
As
1.096 d
559.1
"I
Br
1.471 d
554.3
"I
Sc
0.23 y
889.3
Cd
2.228 d
336.3
"I
Se
0.328 y
264.7
Au
2.694 d
411.8
"I
Ta
0.314 y
1221.4
0.198 y
298.6
487.0
"
Tb
La
1.678 d
Mo
2.748 d
140.5
"
Th
0.066 y
311.9
i
0.668 y
1115.5
"
Zn
0.515 d
1524.6
K
"
Zr
0.175 y
724.2
Sm
1.929 d
103.2
(*) Determined by direct liquid sample analysis.
(**) Determined by both freeze-dried and liquid sample analysis.
2.2.3. Blank Correction
The ice residue which accumulated in the polyethylene bags following the freezedrying process was extremely small, and could not be removed from the bags. Therefore,
bag blank contributions to the ice elemental concentration values had to be corrected.
Before starting the sample freeze-drying process, a preliminary study was done to
determine the elemental concentrations in different batches of polyethylene bags. As a
result, a single batch of bags was chosen because of lower elemental total mass per bag.
The final concentration results and uncertainties for the bag blanks were obtained from the
24 procedural blank bags placed into the desiccators together with the samples during the
sample pre-concentration stages, and they are summarized in Table 2.6.
The total
uncertainties (CT) were calculated by including both the measured variations in the
procedural blank bags (aB) and the analytical uncertainties (OA) by the following equation:
(
T
=
(
+Y A
(2.1)
Contribution of blank correction to the overall measurement uncertainty of the samples is
discussed in section 3.1.
Table 2-6. Container bag-blank concentrations.
Element Concentration Uncertainty Number Element Concentration Uncertainty Number
[ng/g-bag]
of Bags
[ng/-bag]
of
Na
13986
879
24
Sb
2.3
1.0
17
Mg
5218
2891
24
Te
0.46
0.38
4
Al
14386
1398
24
I
23
9
8
C1
1536
555
24
Cs
3.2
1.6
10
K
3499
743
19
Ba
280
131
12
Sc
2.8
0.2
19
La
6.3
1.1
19
Ti
1843
1180
15
Ce
18
6
19
V
121
8
24
Nd
76
76
19
Cr
105
37
19
Sm
1.13
0.16
19
Mn
49
12
24
Eu
0.68
0.38
10
Fe
7019
1905
18
Gd
1.4
0.7
12
Co
9.1
4.0
19
Tb
0.49
0.54
11
Cu
381
269
7
Dy
1.8
0.9
18
Zn
117
65
19
Yb
0.66
0.33
16
Ga
94
66
6
Lu
0.14
0.21
11
As
3.1
0.6
17
Hf
0.86
0.35
10
Se
13
9
17
Ta
8.9
5.0
5
Br
79
32
17
W
1.8
0.7
16
Rb
65
51
3
Ir
0.067
0.046
4
Sr
218
168
9
Au
0.077
0.045
13
Zr
273
226
2
Hg
1.5
0.8
19
Mo
15
4
17
Th
2.3
0.8
18
Cd
2.5
1.4
14
U
3.7
1.3
16
In
0.81
0.36
10
2.3.
Air Content Determination
Before starting the experiments with the actual ice core samples, the total
experimental uncertainty of this method had to be determined. One contribution to the
uncertainty comes from the adsorption of air from the working environment on the sample
surface during the preparation and analysis. This contribution was determined by creating
air-free ice, and subjecting it to the identical sampling and analysis stages to those of real
samples. A special experimental apparatus was designed and constructed (Figure 2.4) to
produce air-free ice.
Vacuum
Liquid N2
ooling coil
Figure 2.4.
Illustration of air-free ice production system.
A polycarbonate desiccator was modified to contain a cooling coil and a purging
nozzle. The cooling coil (0 8 cm x 15 cm) and purging nozzle were made of a copper
tubing (0 8 mm) and aluminum tubing (0 2 mm), respectively. The purging nozzle had a
spiral shaped tip (0 5.5 cm) with small holes in it. Approximately 250 ml of water in a
cylindrical, polyethylene container (0 6 cm x 14 cm) was placed in the middle of the
cooling coil. The purging nozzle was placed in the water container, and the desiccator
cover was closed. The time chart of the experiment is given in Table 2.7. During the first
stage of the experiment a portion of air was released from the water by the application of a
vacuum. Following this, the water was purged with CO 2 gas to enhance the release of the
remaining air. The purging gas was free of Ar since the amount of air in the ice was
determined by measuring the Ar (argon) content by gamma-ray spectroscopy. The gas
used for purging was 99.995 % pure CO 2 with a maximum Ar (argon) content of 5 ppmv,
which is negligible in comparison of the argon in air of 9340 ppmv.
Table 2.7. Air-free ice production time chart.
Time [m]
Action
Temperature [°C]
(inside the desiccator)
0
Vacuum started
25
60
CO 2 flow started
20
19
65
Liquid N2 flow started
118
CO 2 flow stopped
-18
-18
119
Vacuum stopped
120
Liquid N2 flow stopped
-18
Since comparative INAA was used to measure the air content in ice, standards
were prepared from atmospheric air, whose Ar content is well known.
For accurate
volume determinations two polyethylene vials with caps were filled with water, as seen in
the Figure 2.5. Net water masses were converted to volumes by dividing them by the
density of water, 0.998 g/ml, at 20 'C. After these steps the vials were emptied and dried.
They were closed by new caps, and left in the indoor air environment overnight to allow
the interior and exterior air pressures to equilibrate. Later their caps were heat sealed to
ensure air tightness.
Water outlet hole
Water injector
Cap
Polyethylene vial
Figure 2.5.
Air standard vial volume determination.
In addition to the artificially produced, air-free ice samples, a total of nine
specimens from the NBY-89 ice core were sampled for air content analyses to
demonstrate the applicability of the method. Five were chosen specifically to determine
the precision of the method (Figure 2.6a), and the remaining four to understand the
seasonal impact on the air content over a continuous year (Figure 2.6b) of snow
accumulation.
1/11
rlll
--
IVI.ZU m
101.22 m
S
I S5
S2_S1
S41
iS4-" 85
IUI.3U m
101.52 m
S6
.s .
?57
101.54 m
101.24 m
iS
101.56 m I-S
101.58 m
EI----~-~
(a)
(b)
Figure 2.6. Ice sample selection for air content measurement.
All samples, including the air-free blanks, were cut in the same way as discussed in section
3.1 using a special pure nickel blade, the average sample weight was about 3 g.
Immediately after the cutting step, the samples were placed into marked polyethylene
bags, and the bags heat-sealed. The samples were stored in a freezer at -28 'C until the
time of irradiation. Three ice samples were irradiated at a time in a sample carrier for two
minutes in 8x10 1 2 n/cm 2-sec neutron flux. Since the specific irradiation location used is at
approximately room temperature, the duration of irradiation did not cause observable
surface melting.
Once samples were received in the radioactive sample handling
laboratory, they were taken out of the carrier, and each bag was cut open. The samples
were allowed melt on their external surfaces to flush possible surface air contamination
prior to the irradiation by keeping them at room temperature for a few minutes. Following
this, each sample was placed into an unirradiated polyethylene bag, and the bag heatsealed. Each sample then was placed into a second labeled bag for safer handling and
better Ar gas containment in case of melting during gamma-ray counting for the Ar-41
radioactive isotope. After these steps, samples were transferred to the counting laboratory
and counted for 15 min at 7 cm distance from the detector surface. At the end of the
counting time, partial melting had occurred in each sample bag. However, the air released
by the melting of the samples should have still stayed inside the container bags. The heat
sealed air standard vials also were irradiated in the same way and counted for 5 min on
each detector. After letting the samples decay (t1 / 2=1.82 h for Ar-41 isotope) for twelve
hours, they were weighed to calculate the net weights by subtracting the previously
measured container bag weights from the total measured sample weights. Finally the air
content of each sample was determined by comparing its Ar-41 gamma-ray peak to that of
the standard sample.
3.
RESULTS AND DISCUSSION
3.1.
Data Quality Assessment
In the past, many trace element measurements on ice cores suffered from unknown
contamination problems occurring during core drilling, sample handling and preparation
stages (Wolff and Peel, 1985; Gbrlach and Boutron, 1992). Although the measurement of
elements in nanogram and sub-nanogram concentration levels is already a major challenge,
to achieve this goal without contaminating the sample is a more difficult task.
Recognizing the problems in earlier studies in this field, special attention was given from
the beginning of this research to contamination prevention and quality control. A special
difficulty inherent to the study of ice cores is related to the availability of an adequate
sample. The NBY-89 ice core has only a 10 cm diameter, and any one ice specimen
cannot be replaced. The first 50 meters (1647 A.D.-1989 A.D.) of the NBY-89 core was
first used heavily by other researchers and the amount available for this investigation was
terribly limited. Since the pores in the core are not totally closed to the atmosphere over
the upper 40 to 50 meters (firn structure), it would not be representative enough to use
samples from deeper levels, whose pores are closed to the atmosphere (ice structure), for
quality control purposes, although those samples were more available for use. Due to this
limitation, only three pairs of samples (see Table 2.4) were obtained from the first 50
meters depth of the core for duplicate analysis and cross-profiling. Cross-profiling can
also be considered a duplicate analysis of a sample, if there is not a contamination
problem.
The preparation of these three pairs of samples was somewhat more complicated
than that of the rest of the samples. This is due to the need of separating a surface cleaned
sample into two parts (interior and exterior) without contaminating it. Since the sample
weights were limited, it would not be possible to repeat the surface cleaning by shaving
outer layers from each piece after the cutting step. Therefore, a clean way to divide the
samples was necessary. One way of doing this could be melting and collecting the outer
layers in another container on a clean-bench. However, this was not possible for these
samples, since they had a permeable firn structure, which would allow the melted water to
diffuse into the inner section of a sample. To overcome this problem, a high purity nickel
blade was manufactured and mounted on a drill for cutting the samples on a clean-bench.
A simple schematic of this system is given in Figure 3.1.
Clean
polyethylene
Nickel
blade
Ice
sample
Figure 3-1. Sketch of sampling system for cross-profiling sample preparation.
During the preparation of these samples, one section of a pair (17CP2) was dropped and
contaminated accidentally. Therefore, only the remaining two pairs were analyzed for
their elemental concentration profiles.
The results for the inner and outer sections of each pair are given in Table 3.1. As
can be seen in Figure 3.2, the inner and outer sections of each pair showed a good
agreement within the experimental errors for most of the elements. For a few elements,
the results show a considerable difference between the two sections.
However, this
difference does not follow a pattern of contamination, which would always show higher
concentrations for outer (CP2) layers. Therefore, this disagreement is more likely a result
of a combination of factors, namely the cutting process to separate inner and outer parts,
sample inhomogeneity, and analytical uncertainty. Although a pure nickel blade and clean
room procedures were used to cut the samples, some contamination may have occurred
for these elements.
Another possibility is a real concentration difference due to the
difference of each snow flake deposited. However, this argument is somewhat unlikely,
since there are thousands of snow flakes in each section that should create a homogenized
deposition of aerosols. Since this extra cutting step was not involved for other samples
used in this work, it is likely that elemental concentration results on those samples will
have less analytical uncertainty compared to the control samples. Considering that for
elements, such as aluminum and sodium, that are readily available in the sampling and
preparation environments, the results show satisfactory agreement between the inner and
outer sections, any serious and systematic contamination problem influencing the results
can be ruled out.
Table 3-1.
Concentration results for cross-profiling samples [ng/g-ice].
23CP1
(inner)
Na
Al
Cl
K
Sc
Ti
V
Cr
Mn
Fe
Co
Zn
As
Br
Mo
Cd
Sb
La
44±5
10±4
91+11
23CP2
(outer)
51±5
9±+3
88±10
0.060±-0.003
0.051+0.003
10.0±4.2
0.15+0.04
14.4±3.8
0.15±+0.03
0.37±+0.06
3.25±0.05
12.9±3.6
0.65±+0.09
0.64±0.03
11.5±4.8
0.009±0.010
4.7±0.4
0.004+0.002
0.08±0.09
0.007+0.012
0.002+0.004
0.0731+0.005
0.001+0.003
0.014+0.008
10.6±0.7
0.005±+0.002
0.08-0.07
0.022-0.011
0.009-0.005
0.067+0.004
0.006_+0.002
.
28CP1
(inner)
42+5
12+4
87+11
1.2+3.5
0.058+0.004
5.7±3.0
0.01+0.02
0.39-0.08
0.81±0.03
7.0±4.3
0.010-0.009
6.7±0.5
0.001-0.002
0.12±+0.08
0.011-0.011
0.003+0.005
0.026+0.003
0.006+0.003
28CP2
(outer)
48+5
5±3
108+13
5.9±4.6
0.057+0.003
3.1+2.6
0.01-0.02
1.01-0.07
0.87±0.03
15.1±4.0
0.017_-0.008
11.0±0.8
0.006--0.002
0.19±0.09
0.007-0.009
0.014_+0.007
0.037+0.003
0.002+0.002
Aluminum
Scandium
^ ^•
'
0.07
18
0.06-
o14
-
~ :55
::::::~:~;Z·5
0.05-
.
i~i~i~j
55555'
55
0.04-
0 68 S20-
I115
......
'
23CP2
28CP1
·5·-
t.:~:~:~::::~s ~
·~5·
·;·;·:·.·.zz::
0.03S0.02-
55:~
.v:
...
........
··Y I·-1·123CP1
~
5i~5·~
i·5·Zi··:~:
·ns;s·~l
~i
5555555
:-:s~
·5·Si·I
~s~
0.
28CP2
23CP2
23CP1
28CP1
~
s~
55
:::::::::~:::
:~:~:::
:·:5·:·:·
·:
cs
:5;:;~;:··
,s~:
-~
28CP2
Sample ID
Sample ID
Manganese
Iron
20
18
16
,'9 3
0
0
02
12
0,
108
0
23CP1
23CP2
28CP1
5
-,f
0.
Mle
0
uV1
e0
16
14
0
--
23CP1
28CP2
23CP2
28CP1
Sample ID
Sample ID
Titanium
Lanthanum
28CP2
--
20
000
tl &lt•
16
"b14
12
10
u
U 0.008
-
S0.007
-
8
o 0.006
o 0.005
0.004
6•
0.003
G 0.002
0.000
2
IJ
23CP1
23CP2
28CP1
Sample ID
28CP2
iT
-
-
-
-
-
71 .
r55-
.·
.....
-
0.000
23CP1
23CP2
28CP1
28CP2
Sample ID
Figure 3-2. Elemental concentrations measured in cross-profiling samples (CP1 and CP2
denote inner and outer samples, respectively.
Molybdenum
Cadmium
II^^^'
""4
0.024 0.022 -
8
T
0.030 -
0.020S0.018-
M 0.025
L
=S0.014
0.016- -
.0 0.012 -
.......
....
8
0.010-
0.005 -
U 0.002-
0.000 - I
_________
23CP1
0.000 -
23CP2
28CP1
,· · ~-~
-
0.015
0.010-
So0.0080.0060.004-
22222
~f~5~-'
0.020 -
iiji~ii~
t~
pr
23CP1
28CP2
~i
-~s
,,
______·____
23CP2
~f;
~
"·"~""`
"""""'
28CP1
28CP2
l
Sample ID
Sample ID
Sodium
Chlorine
6so
T
ggg--g
-50
0
*
T
120
-
~
100
-
~::::~i~
40
~
030-2
~t~-~
20
~ss~
10
~
ff
~ts~ ". .
"'"
T
X:K
:·:
Sso
....
.....
..
..
..
......... ....
60
~i
~·
F~ss~s~
~~s~
ss~
·z~f;ss
t~
s-.~s~
~
.sss·`·-
0
'-----
23CP1
23CP2
28CP1
28CP2
23CP1
Sample ID
23CP2
28CP1
28CP2
Sample ID
0.0
0
Arsenic
Antimony
0.009
0.008
8
7
0.016
T
-
ro 0.007
-
c 0.006
o 0.005
V
-
•4
3
0o.
i
-
o 0.0X
o0
-
U
1
0.X
-
0.0(1
-
0
0.01 I
-
23CP1
23CP2
$81
28CP1
Sample ID
Figure 3-2. (cont.)
28CP2
0.004
S0.003
S0.002
0.000
0.000
23CP1
23CP2 28CP1
Sample ID
28CP2
1
Bromine
Chromium
0.30
0.25
-
0.20
.
-
S015
.
...
..
..
.
0=1
... ....
-
C!
........
.
......
.....
..
0.10
S0.05
....... ...
U
0
0
0.00
23CP1
23CP2
28CP1
28CP2
23CP1
23CP2
28CP1
Sample ID
Sample ID
Vanadium
Zinc
28CP2
0.20
018
0.16
b 0.14
0.12
S010
0.08
=
0.06
0.04
O 002
0.00
-
-
-
-
-
S12-
IT T
U
T....
.
.
...
.......
...
..
..
..
..
.
.
...
..
.
.........
....
:~~
....
..
..
..
..
.
S10-
S
0
-
E
8-
0642-
-
:e.'x~;s
-:···j
~~ i
~:·1~ ·
:LSOZ
:·:
X~~`l
·:~~t ::·
··~~j
~
~
·~:oll·
0-
-
23CP1
23CP2
28CP1
Sample ID
Figure 3-2.
~;O · ·
(cont.)
28CP2
23CP1
23CP2
28CP1
Sample ID
.-. .-.. . .
28CP2
After this assessment, the procedures for blank correction and experimental
uncertainty calculation steps will be described. As was discussed in section 2.2.3, sample
container blanks were analyzed and their average elemental concentrations were
calculated. Define [Ck]sample and [Ckblank as the concentrations of element k in a sample
(includes ice and its container) and blank container, Mice and Mblank as the ice mass and
container mass. One can then calculate the net concentration in ice as follows:
[Ck]ice = { ( [CkIsample X (Mice + Mblank) )
( [Cklblank X Mblank-)
}/ Mice
(3.1)
Since,
Msample = (Mice + Mblan)
=
(3.2)
ce
the final result can be given as:
[Ck]ice = [Ck]sample - { ( [Ck]blank X Mblank) / Mice
}
(3.3)
Error propagation calculations were performed in each step to obtain the final
concentrations. Uncertainties due to sample weighing, container blank measurement, and
gamma-ray spectrometry counting statistics were all included. Although it would be
desirable to include the uncertainty due to the preparation and handling steps of samples,
assessment of this uncertainty was not possible for the reasons mentioned above. One
alternative to assess this uncertainty could be the use of artificially created duplicate
samples. However, it would be very difficult to simulate the real samples which had firn
structure (pores open to the atmosphere) and low elemental concentrations.
Median uncertainties of the final concentrations for the 18 elements with
significant observation frequency (> 70 %) are given in Table 3.2. For most of the
elements, the major contribution to the total uncertainty on the final concentrations came
from the blank correction step for sample containers. Plots of cumulative percent data
with respect to overall relative uncertainty are given in Figure A. 1.in Appendix A.
Table 3-2. Median uncertainties on the concentrations of elements with significant
observation frequency.
Number of
Median %
Element
Number of
Median %
Element
samples
Uncertainty
samples
Uncertainty
97
15
Mn
97
11
Na
95
37
Fe
72
123
Mg
97
13
Zn
97
24
Al
97
30
As
97
13
C1
95
48
Br
73
57
K
66
128
90
Mo
52
Sc
95
8
Sb
73
112
Ti
89
La
77
89
V
78
84
56
Sm
97
9
Cr
3.2.
Time-Series Trends
The final concentrations for the main group of 97 samples analyzed and the
statistical summary information regarding this data set are given respectively in Table A.1
and Table A.2 in Appendix A. Since there was more than one sample in some years, and
some samples coincided with two or more years, the depth-date calibration data (Table
A.3 in Appendix A) provided by Osada (1994, personal communication) was used to
calculate the concentrations for a specific year of interest. Note that the provided dating
calibration data is more precise for the period between 1941 and 1989 compared to the
period between 1711 and 1941.
Annual concentrations were calculated by weighted
averaging of the samples associated with a specific year, and the percent length of each
sample portion that coincided with that year was used as the weight coefficient for that
sample. These final annual average concentrations are given in Table A.4 in Appendix A.
In these calculations missing values were replaced by the most probable values obtained by
log-normal distribution curve fitting to the original data, and the results of these
calculations are given in Table A.5 in Appendix A. The physical and mathematical bases
of this step are explained in section 3.3.2.
One parameter that is helpful in evaluating whether or not a source category might
be an important contributor for an element of interest is called enrichment factor (EF) and
defined as (Gordon et al., 1971):
IX]
EFx=
[Y]I sample
sa(3.4)
{[Y] reference
where,
[X] : Concentration of element of interest
[Y] : Concentration of element used as marker for a source category
This parameter compares the ratio of these elements in a sample medium to that of a
reference medium such as soil, sea water, or plume from a volcano. In a physical sense,
the EF parameter shows whether a source category might be a candidate for the observed
concentrations of an element or not. When this parameter is less than 5, it is assumed that
the element of interest is not enriched significantly with respect to the reference medium.
This implies that medium might be a candidate as a source category for that element. In
an ideal situation, the EF of an element that originates only from a specific source of
interest (e.g., soil dust) should be 1 at the receptor site.
However, due to the
inhomogeneities on the source compositions and possible physical and chemical
fractionation effects during the transport to the receptor site, this parameter deviates from
1 in most cases. That is why EF values as high as 5 may not be claimed with certainty to
be real in most cases. Crustal and marine enrichment factors for some elements measured
in this work are given in Table B. 1 and Table B.2 in Appendix B respectively. Aluminum
and sodium were used as the marker elements for crustal and marine EF calculations. The
crustal contribution to the total sodium concentrations was subtracted to find the marine
component, and these corrected sea-salt sodium concentrations (Na.) were used in the
marine EF calculations. Taylor's (1972) standard crustal and Goldberg's (1963) standard
marine reference compositions were used in the calculations.
One can safely assume that the elements measured were deposited almost entirely
as components of aerosols, although some volatile and highly soluble elements might also
have been deposited in individual form. In Antarctica, aerosols can be classified into four
general categories with respect to their origin, as crustal, marine, volcanic, and
anthropogenic (Dick, 1991; Tuncel and Zoller, 1995). Although there might be some
extraterrestrial contribution, it is thought to be very minor in comparison (Tuncel et al.,
1989). A few certain elements are almost entirely associated with a certain aerosol source
category.
3.2.1. The Marine Aerosols
The two major elemental components of marine aerosol used as marker elements
are sodium and chlorine, mostly associated with the sea-salt component. Since there
might be considerable loss of chlorine due to chemical fractionation during transport
(Legrand and Delmas, 1988), and significant contribution of chlorine from volcanic
emissions from time to time (Kyle and Meeker, 1990), Sodium was chosen as the marker
element for marine aerosols.
The time-series trend for sea-salt sodium (Na.)
concentrations is given in Figure 3.3. In this plot, and the ones following, the abscissa is
not given to scale, so the data covering the time period from 1926 A.D. to 1989 A.D.,
which has continuous annual data, is clear. The data is comparatively sparse prior to that
period. As can be seen, a significant and sharp increase of concentration occurs between
1969 and 1989. Concentrations fluctuate from year to year throughout the time periods
both before and after this increase, but do not show a monotone trend within a time
period. The ratio of average concentrations in the post and pre 1969 period is 3. This is a
sudden and significant increase in the last two decades. Although not as significant, there
seems to be another similar era between 1870 and 1895. However, due to the sparse data,
it is difficult to draw any conclusions for this earlier period.
As mentioned earlier, due to the high vapor pressure of chlorine, the possibility of
volatilization loss during the freeze-drying steps exists, so this element was not determined
from the freeze-dried samples but directly from small (1-2 g) melted samples. Therefore,
it is more meaningful to compare the chlorine concentrations with the sodium
concentrations measured within the same small samples. In further discussions these
specific measurement results for chlorine and sodium will be designated as Cliq and Naiq,
respectively. Figure 3.4 shows the concentration time-series trends of ClIq and Nalq. As
0
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[93!-6/Bu] uoqleilueouoo
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seen, these elements are well correlated with each other, as expected because of their
common origin. They also exhibit a sharp increase within the last two decades. Two
possible causes of this increase are a more efficient aerosol mixing over the Antarctic ice
sheets and/or an enhanced source strength in the southern oceans. It is helpful to consider
the production and transport mechanisms of marine aerosols to be able to comment further
on this behavior.
The marine aerosols, made up of mostly sea-salt particles, are released from the
sea surface into the air mainly by two well-known release mechanisms, which are the
surface films in breaking waves on the ocean and jet drops from rising air bubbles (Shaw,
1989).
Air can be brought into the water by raindrops, snowflakes, supersaturation
(produced by temperature rises), and whitecaps, with the last being the most effective
(Blanchard and Woodcock, 1980). Sea-salt aerosols were shown to be as small as 0.03
gIm (M6szaros and Vissy, 1974) and as large as several hundred microns (Junge and
Jaenicke, 1971) in the ocean surface air, although only 1-2 % are small enough (r < 0.5
pm) to arrive on the Antarctic ice sheets (Junge, 1963). It was also shown that wind is an
important factor in the source strength of sea-salt aerosols (Fairall et al., 1983). An
increasing number of aerosol concentrations in the Aitken mode (r < 0.1 pm), associated
with higher sea surface temperatures and stronger surface winds, were observed
throughout the tropical trade wind region (Lal and Kapoor, 1992). Increasing storminess
is one of the reasons for the enhanced marine aerosol concentrations observed in central
parts of Antarctica during the winter seasons (Cunningham and Zoller, 1981; Parungo et
al., 1981; Tuncel et al., 1989). The general source region for the warm, marine aerosol
enriched air seems to be the Ross-Amundsen-Bellingshausen seas (Bodhaine, et al., 1986).
The seasonal behavior of the sea-ice cover in these regions was suggested as a defining
factor for the observed discreet sea-salt episodes that accompany warming during wintersummer transitions (Hogan et al., 1990).
The transport of marine aerosol from the oceans to the Antarctic ice sheets takes
place through advection and turbulent diffusion in the atmosphere.
However, this
transport is somewhat complicated by the special meteorological features around
Antarctica. The especially intense and highly zonal circumpolar vortex is an important
barrier for the aerosol transport to the interior of the ice sheets (van Loon, 1972).
The
circulating cyclonic storm systems that form over the oceans in the vicinity of the polar
front (Wilson, 1968) and migrate clockwise around the continent due to the circumpolar
vortex can rarely penetrate this barrier (Shaw, 1979). The cyclonic wind system and
surface temperature inversion are weaker during the summer season, which results in more
favorable conditions for aerosol transport into the ice sheets compared to the winter
season (Cunningham and Zoller, 1981; Hogan et al., 1984; Tuncel et al., 1989).
Therefore, lower marine aerosol concentrations observed during the summer months
should be the result of calm weather conditions that results in the less efficient production
and intrusion of aerosols into the ice sheets. An upper troposphere-lower stratosphere
mixing was demonstrated, especially during the spring season, both in lower latitude
regions and Antarctica (Danielsen, 1968; Ellsaesser, 1983; Wagenbach et al., 1988;
Murphey et al., 1991), which might indicate a stratospheric transport route for lowerlatitude water vapor and aerosols into the Antarctic atmosphere. However, it was shown
that not this transport mechanism but an enhanced source of aerosols in the maritime polar
air source region was the main reason for the observed spring time marine aerosol
concentration increase at the South Pole (Hogan et al., 1990).
In light of these details about the production and transport of marine aerosols,
production is more likely to be the defining factor for the enhanced deposition within the
last two decades, although the possibility of more efficient aerosol mixing over the
Antarctic ice sheets cannot be ruled out. Since Antarctica is surrounded by oceans, the
source strength for marine aerosol is stronger and transport range is shorter than those of
other aerosols. Therefore, it is expected that significant changes in the oceans and their
surroundings will affect the marine aerosol concentration in Antarctica faster and stronger
than the other aerosol categories. Changes in the sea-ice extent, sea surface temperature,
ocean currents, ocean microbial activity, wind strength, precipitation patterns, and air
temperature are among those that can affect marine aerosol concentrations. In reality, all
of these parameters are components of the ocean-atmosphere system and they strongly
affect one another.
For newly produced sea-salt aerosol, the chlorine to sodium ratio reflects the ratio
within the sea-water which is 1.8 (Loureiro et al., 1992).
However, several studies
showed chlorine depletion in the aged marine aerosols collected in the Antarctic
atmosphere (Maenhaut et al., 1979; Bodhaine et al., 1987; Legrand and Delmas, 1988;
Guerzoni et al., 1992;), as well as in the tropical marine atmosphere (Kritz and Rancher,
1980). Measurements of the marine aerosols collected over the tropical and equatorial
Pacific showed a 40 % loss of chlorine from the submicron particles, while no loss was
observed for larger particles (Raemdonck et al., 1986). The overall reaction responsible
for this depletion is thought to be (Keene et al., 1986);
NaCl (p) + H => Na' (p) + HCI (g)
where "p" and "g" denote the particulate and gas phases, respectively. As a source of
hydrogen ions, atmospheric acids H2SO4 and HNO 3 have been proposed (Legrand and
Delmas, 1988). Figure 3.5 shows the Cliq to Nalq concentration ratios obtained in this
work. The overall average ratio is 2.03-+0.04. Since these measurements were done in
small samples, which cannot represent annual average concentrations, these values should
be taken as informational values due to the possible seasonal differences in this ratio.
However, one interesting feature on this plot is the apparent drop of chlorine-to-sodium
ratio after 1940. Pre- and post-1940 ratios are 2.24±0.08 and 1.87±0.04, respectively.
Two reasons could explain this behavior; one is the possibility of increasing crustal
contribution to the total sodium budget during the post-1940 period, and the second one is
the possibility of higher chlorine contribution from volcanic activities to the total chlorine
budget during the pre-1940 period. As will be discussed in sections 3.2.3 and 3.2.4, both
of these possibilities seem likely to contribute to this trend.
The average marine Enrichment Factor (EFm) results calculated from Table B.2 in
Appendix B indicate that oceans are the main source for the elements sodium
(EFm,=1.1_0.03), magnesium
(EFm=1.3_0.2), chlorine
(EFm=3.8±0.4), and bromine (Efm=1.2+0.1).
(EFm=1.3±0.03), potassium
a,
S-j
O0
U'c:
o
or=
E
0
C)
"I3
*Mi
!
f•
1,i
[bB N / [bIi
]
3.2.2. Possible El Nifio Events-Marine Aerosols Connection
When one looks at the major changes in the ocean-atmosphere system within the
last two decades, one sees that the occurrence of the so-called El Niflo Southern
Oscillation (ENSO) events in the Pacific Ocean increased considerably compared to the
previous five decades (Fig 3.6). Although it is not the scope nor the intention of this work
to get into much detail about this natural phenomenon, a short summary might be useful
before getting into further discussion.
The term El Nifio (Spanish for the Christ Child) was originally used for a weak
warm coastal ocean current which annually flows southwards along the coasts of Ecuador
and Peru in the first three months of the year (Burroughs, 1992).
In some years,
abnormally high and persisting temperatures disrupt the ecological balance much more
seriously and in scientific usage the term El Niflo has come to be associated with these
extreme inter-annual events. The Southern Oscillation, named by Sir Gilbert Walker in his
papers in the 1920's and 1930's, originally referred to the oscillating atmospheric pressure
difference between the Pacific and Indian Oceans and its connection with temperature and
rainfall patterns (Burroughs, 1992). Essentially, this pressure difference is the driving
force for the easterly trade winds from the eastern to western Pacific. Later in the 1960's,
Jacob Bjerknes was the first scientist to see a connection between unusually warm seasurface temperatures and the accompanying heavy rainfall in the eastern equatorial Pacific
and weak easterlies (Wallace and Vogel, 1994). This discovery led to the recognition that
the El Niflo and Southern Oscillation are parts of the same phenomenon which is now
called ENSO.
During normal years, the easterly winds that blow along the equator and the
southeasterly winds that blow along Peru's and Ecuador's coasts drag the warm surface
water along with them towards the western Pacific region, and cold deep water replaces
this warm surface water. This regular movement of ocean currents ceases during El Nifio
years, when the weakening easterly trade winds are no longer able to drag the warm
surface water from the eastern to western Pacific. As a result, the sea-surface temperature
distribution and the precipitation pattern become drastically different than in normal years.
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During these years, sea-surface temperatures and precipitation rates increase in the central
and eastern Pacific regions, while decreasing in the western Pacific region. Although the
exact reason(s) for the initiation of ENSO event is(are) not known, its effects on the
climate are quite visible today. Changing temperature, precipitation, and wind patterns
especially in Australia, South America, and part of Africa are drastic.
After this short review one can comment on the possible connection to the
observed marine aerosol concentration increase in Antarctica (this work). The observed
changes on the sea-ice extent, sea-surface temperature distribution, precipitation patterns,
and storminess over the Pacific Ocean during the ENSO events are likely to affect the
marine aerosol production. It was already mentioned in a review article (Carleton, 1992)
that the sea-ice-circulation anomalies might have some connection to the ENSO, and the
extent of the sea-ice has an effect on the migration of moisture sources important for the
sea-salt aerosol accumulation on the Antarctic ice sheets. It was also mentioned by the
same author that signatures recorded in ice cores hold the best promise to obtain longerterm data. Also the Pacific sector of West Antarctica, from which the NBY-89 ice core
used in this work was obtained, appears to hold promise for detecting the ENSO signal,
although some problems might arise from the dominance of the annual snowfall regime by
relatively few cyclonic events. Therefore, the enhanced marine aerosol concentrations
observed in this work might have some relationship to the increasing ENSO activity within
the last two decades.
One way of checking this hypothesis is to search for possible periodicities in the
Na, concentration time-series data and to compare these to the previously identified
periodicities on the ENSO related parameters, such as sea level pressure (SLP), sea
surface temperature (SST), and precipitation patterns in the Pacific region. For this
purpose a computer program developed by Khalil and Moraes (1995) was used. This
program relies on the Linear Least Squares Spectral Analysis (LLSSA) method which is a
simple method of time-series analysis based upon linear least squares curve fitting. The
main idea of this method is to find the best fit sinusoid to the data for each member of a
set of periods and then assign a weight factor to each fit by calculating the power (square
of the amplitude of the fit) for that period (Khalil and Moraes, 1995).
The major
advantages of this method are the possibility of unevenly spaced data analysis for any
length period and easy determination of statistical significance for each period. Detailed
information about this method can be found in literature (e.g., Bloomfield, 1976; Moraes
and Khalil, 1993; Khalil and Moraes, 1995).
The power spectrum of the Na. time-series data (1711 AD-1989 AD) for periods
between 2.1 and 15 years are given in Figure 3.7. In spite of its highest power value, the
2.0 year period was eliminated due to its very high uncertainty. Figure 3.8 shows the
measured Na. time-series data (1926 AD-1989 AD) together with the curve fitting using
the most significant period (4.2 years). In this fit the general trend seems quite close to
the real data except the absolute concentration values. This difference comes from the use
of a single period for the fitting. When the top eight periods were fitted (2 year period
excluded) to the same data, the two curves showed much better agreement as expected
(Figure 3.9). The power spectrum calculation results for two different time intervals are
summarized in Table 3.3.
Table 3-3. Periodicities and their power values in Na,, data set.
Time Period
Period
power 1
[year]
(AD)
2.0
802+±1806
1711-1989
3.8
149+129
4.2
165±137
9.1
136±123
11.7
139+127
31.4
367+_195
34.6
319±186
46.5
310±180
55.8
525±221
98.1
686-243
160.0
735±283
1926-1989
2.0
1292±12690
3.8
191+191
4.2
207_+199
5.7
149+170
7.5
122+155
9.1
124±156
11.7
107+145
17.1
119±155
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In an independent study, periodicities on the variation of the Southern Oscillation
(SO) were identified from accumulated Darwin (Australia) mean sea level pressure
(MSLP) anomalies (Zhang and Casey, 1992). This analysis, covering the interval between
1882 and 1989, showed significant periods between 2 and 6 years. It was also reported
that (Burroughs, 1992) the spectral analysis of the annual SO figures in Australia and New
Zealand showed a series of peaks, the most marked of which are at 3, 3.75, around 6,
around 9, and 10 to 12 years. As can be seen, these periods are quite similar to the
periods found in this work. Therefore, the hypothesis about the possible relationship
between the ENSO related events and sea-salt sodium concentrations deposited on the
Antarctic ice sheets has some validity. However, a word of caution is necessary because
of the possible problems with the time-series analysis of environmental data as summarized
by Burroughs (1992), and more detailed and sophisticated statistical analysis studies are
necessary before reaching any final conclusion.
3.2.3. Crustal Aerosols and Their Possible Role in Polar Atmosphere
Crustal aerosols are customarily represented by the marker elements aluminum,
scandium, and, to a certain extent, iron. In this work aluminum was used as the marker
element for crustal aerosols. The time-series trend of aluminum concentrations is given in
Figure 3.10. As seen, there is a significant upward trend after 1980, while the overall
concentration trend is reasonably constant prior to that time with the exception of
sporadic episodes in certain years. The ratio of average concentrations in the post- and
pre-1980 periods is 3.0±0.1. This is a significant increase in a considerably short time
period. Although not as significant, there is also some enhancement between 1969 and
1980. The ratio of the average concentration between 1969 and 1980 to that of the pre1969 period is 1.4±-0.1. This increase is also evident for scandium which is another mainly
crustal origin element (Figure 3.11). Although the aluminum and scandium concentration
trends are similar in general, they differ at certain years mainly because of the higher
measurement uncertainties for scandium caused by near-detection limit concentrations in
the samples. The number of missing values for certain years might bias scandium. Figure
3.12 shows the crustal enrichment factor time-series trend for scandium. Even though the
EF for scandium is expected to be close to one, it is only 0.22+0.03 on the average. This
behavior was also observed in some previous atmospheric aerosol sampling programs in
Antarctica (Tuncel et al., 1989). Although it seems that the post-1948 era has higher
scandium EFs compared to that of the pre-1948 era, high uncertainties on the data make it
difficult to be sure about the reality of this behavior.
The average crustal Enrichment Factor (EFt) results calculated from the Table B. 1
in Appendix B indicate that crustal contribution is the main source for most of the
elements measured in this work (Table 3.4). However, this conclusion does not rule out
the possibility of some other episodic contributions from specific sources, such as
volcanoes. Among these potentially crustal origin elements, magnesium and potassium
also come from the oceans at the same degree as shown in the previous section.
Table 3-4. Average EFe results for potentially crustal origin elements.
Element
Average EFe
Element
Average EFe
Mg
K
Sc
Ti
V
Mn
1.9±0.3
1.9±+0.2
0.2±0.03
2.9_0.5
1.5±0.2
1.2±0.05
Fe
Co
La
Ce
Sm
1.4±0.1
1.0±0.2
2.1±0.2
2.0±0.3
1.6±0.1
Since 99 % of Antarctica is covered with ice, and the continent is far from other
land areas in the Southern Hemisphere, the major mechanism for crustal aerosol input into
the Antarctic ice sheets is expected to be long range atmospheric transport from distant
source regions. Although some small arid areas in Antarctica, such as the Transantarctic
Mountains, also were proposed recently as potential crustal aerosol source areas for the
ice sheets (Guerzoni et al., 1992), these frozen soil areas are not considered as important
sources for the central parts of the continent (Cunningham and Zoller, 1981; Dick, 1991).
Therefore, increasing crustal aerosol input into the ice sheets should be either due to
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increasing source strength at some distant land areas and/or increasing transportation
toward the Antarctic from those areas. This view is supported by the observed seasonal
crustal aerosol concentration trends, which show summer maximum and winter minimum
(Cunningham and Zoller, 1981; Wagenbach et al., 1988; Tuncel et al., 1989).
Since
scavenging is more effective during the winter season due to increasing precipitation,
aerosols are less likely to survive the long-range transport over the oceans. In addition,
the cyclonic wind system and surface temperature inversion are weaker during the summer
season, which result in more favorable conditions for aerosol transport into the ice sheets
compared to the winter season (Cunningham and Zoller, 1981; Hogan et al., 1984; Tuncel
et al., 1989).
Deserts, which cover approximately one-third of the global land surface, are the
most important crustal aerosol sources (Jaenicke, 1993). Due to extreme physical and
chemical weathering processes, some parts of deserts (dry valleys) produce very high
numbers of small size aerosols that can participate in long-range transport (d'Almeida and
Schiitz, 1983).
Wind patterns over the deserts affect both aerosol production and
transport into the atmosphere. The prime candidates for providing crustal aerosols in
Antarctic ice sheets are the Kalahari (south Africa) and Atacoma (south America) deserts
and the deserts of central and western Australia (Shaw, 1989). Results from a modeling
effort using the Atmospheric General Circulation Model (AGCM) showed that dust
contribution to West Antarctica, where Byrd Station is located, is dominated by Australia
and South America during the austral summer season and by Australia during the austral
winter season for the present day conditions (Gaudichet et al., 1992).
Since the increasing crustal aerosol concentration trend observed after 1980 is
quite monotone, it seems more likely that this reflects changes in production rather than
transportation.
It is somewhat unlikely that the transportation efficiency would be
increasing continuously over the last decade. It also seems unlikely that the local aerosol
source strength would increase in this way.
Therefore, the remaining possibility of
increasing aerosol source strength in the distant Southern Hemisphere land areas seems
likely to be the reason. After the major 1982-83 ENSO event, the changing weather
patterns in the Pacific created large scale droughts in parts of Australia, Indonesia, South
America, and Africa, as well as disastrous forest fires in Indonesia and Australia (Wallace
and Vogel, 1994). Considering the frequent ENSO events over the last two decades, it is
highly likely that enhanced aerosol production could be caused by increasing erodable soil
areas, mainly due to the desertification of inner land areas and sea level drop in the
Western Pacific region during ENSO events. In addition to the changes in aerosol source
strength, changing weather patterns (Wallace and Vogel, 1994) also might have affected
the transport of these aerosols. However, it is not known with certainty whether or not
these weather pattern changes affected the aerosol transport over the Antarctic ice sheet.
It was the general assumption until recently that crustal aerosols were produced
larger than several tenths of a micrometer, and most of the measurements in deserts and
arid land areas have been designed for those sizes (Jaenicke, 1993). One of the reasons
for this assumption was the impracticality of smaller size particle production by physical
weathering processes (Shaw, 1989).
In addition, the domination of particle mass
distribution by larger particles (Gomes and Gillette, 1992) attracted more interest for their
measurement, so that approximate mass deposition fluxes could be obtained. However, it
was suggested later that dissolution of water-soluble minerals might reduce the size of
particles (Schroeder, 1985), and particles of radii as small as 0.01 pm with frequent
number distribution peaks below 0.1 pm were measured (Junge, 1977; d'Almeida and
Schiitz, 1983). It was reported that background aerosol originating from the continents
dominates the aerosol load in the middle and upper troposphere almost globally, and it has
the size range of 0.03 pm to 20 gm (Junge, 1977). On the other hand, marine aerosol is
removed efficiently over the oceans due to the high humidity and cloudiness together with
its high solubility (Junge, 1977).
As mentioned before, a certain amount of mixing occurs between the upper
troposphere and lower stratosphere. Therefore, it is possible that some of the crustal
aerosol in the upper troposphere might mix into the stratosphere during its transport to the
Antarctic. The residence times of aerosols in the upper troposphere and stratosphere can
be up to a month or a year, respectively (Barrie, 1985), and are long enough for longrange transport of these aerosols into the Antarctic atmosphere.
This possible
stratospheric residence of crustal aerosols brings up the question of whether or not there
might be some impact on the heterogeneous chemistry of the stratosphere due to the
increasing crustal aerosol concentrations.
One important and famous example of the
heterogeneous chemistry is the spring-time stratospheric ozone depletion mechanism in
Antarctica.
Following this example, the annual average ozone concentrations
homogenized between the 600 S and 900 S latitudes from the Total Ozone Mapping
Spectrometer (TOMS) ozone data set provided by NASA Goddard Ozone Processing
Team were retrieved for the period between 1979 and 1989. Figure 3.13 shows the timeseries trends of ozone and aluminum concentrations between 1979 and 1989. The reason
to start with the year 1979 is the lack of satellite measurement data for globally averaged
values prior to this date. However, land-based measurements for the Antarctic spring time
ozone concentrations did not show a trend prior to late 1970's (Bojkov, 1986).
Interestingly, a strong negative correlation (-0.9) exists between these two parameters and
the linear regression lines fitted to the data have very close slopes with opposite signs (4.4 for ozone and +4.8 for aluminum). Although the short time period (11 years) prevents
drawing a strong conclusion from this correlation, it is worth thinking about this result in
light of the recent findings about the importance of heterogeneous chemical processes,
mainly due to the formation of polar stratospheric clouds (PSC), on the formation of the
Antarctic ozone hole. General information about the ozone depletion mechanisms is
summarized in Appendix E.
Aerosol concentrations in the stratosphere are much lower than those of the
troposphere. The most abundant aerosol type in the stratosphere is sulfuric acid solution
droplets, which are formed by the condensation of sulfuric acid gas that is produced from
highly available sulfur dioxide gas through photochemical reactions (Hamill and Toon,
1991). These sulfate aerosols, with diameters around 0.14 gm, contain approximately 25
% water and 75 % sulfuric acid and are believed to be in a supercooled liquid state. In
addition, particulate material of natural and anthropogenic origin can also penetrate to the
stratosphere from the troposphere and outer space. Among the terrestrial aerosol sources,
strong volcanic explosions are best known for their high gaseous and particulate matter
injection capability into the stratosphere. In a similar way, particulate material originating
from the ablation of meteorites entering the earth's atmosphere is assumed to be the major
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extraterrestrial source contribution to the stratosphere. However, information about the
stratospheric particulate material composition is limited due to the complexity of sampling
at those altitudes, together with the very low concentrations and small sizes of particles.
If the increasing crustal aerosol deposition trend observed in these Antarctic ice
samples is an indication of increasing production and transport from the mid-latitude
regions through the upper and middle tropospheric layers as discussed earlier, it might be
possible for some of the smaller size aerosols to penetrate into the stratospheric layers and
participate either in the nucleation processes to form the polar stratospheric cloud particles
(PSC) (see Appendix E) or directly in the heterogeneous reaction mechanisms.
This
participation might be in different ways, such as nucleating sulfuric acid and water vapor
as sulfuric acid solution droplets or frozen particles, nucleating water ice particles,
nucleating nitric acid trihydrate (NAT) particles (see Appendix E), or catalyzing
heterogeneous reactions directly on the particle surfaces.
It was already suggested that heterogeneous reaction mechanisms at mid-latitude
stratospheric regions are likely to be responsible for the observed ozone depletion trends
after large scale volcanic eruptions. For example, column NO 2 depletion was observed at
northern mid-latitudes during the winter of 1982-83, following the eruption of El Chich6n
in Mexico (Hofmann and Solomon, 1989). Similarly, low stratospheric ozone levels were
observed in the mid-latitudes in the months following the eruption of Mount Pinatubo in
Philippines (Grant et al., 1992). One example of volcanic impact on the polar regions is
the observed ozone reduction simultaneously with higher aerosol concentrations in the
lower stratosphere in Antarctica after the August 1991 eruption of Mount Hudson in Chile
(Hofmann et al, 1992).
However, outside the polar caps, the temperature in the
stratosphere seldom drops below -63 'C, which is considerably warmer than the PSC
formation temperatures by known mechanisms (Garcia, 1994). Therefore, some other
mechanisms must exist for the observed ozone depletion events due to heterogeneous
processes.
An attractive possibility is PSC formation at higher temperatures due to interaction
with other solid particulate matter. It is already known from the tropospheric cloud
formation mechanisms that cloud droplets can stay in a supercooled liquid state at much
lower temperatures than the freezing point unless they are activated as ice nuclei (Barrie,
1985). This activation mechanism is known to be selective since only some of the cloud
droplets become ice nuclei and can form snowflakes through condensation growth (Barrie,
1985). It is also known that clay minerals covered with soluble sulfur particles are the
most efficient ice nuclei starters (Kumai, 1976). They cause ice nuclei formation either by
acting as nucleation particles or by causing ice shattering when they come in contact with
supercooled droplets (Beard, 1992). In addition to increasing heterogeneous reactions,
these aerosols can cause increasing denitrification and dehydration of the stratosphere
through sedimentation of large cloud droplets or frozen particles due to selective
condensation growth process, thus causing further ozone depletion due to the reasons
discussed in Appendix E.
Another impact of the increasing crustal aerosol production and the subsequent
deposition on the oceans might be on the organic sulfur production in oceans due to
increasing marine biological activity. Iron is known to be essential for the growth of
microorganisms in the oceans, and aeolian mineral dust is the principal source of marine
iron in many areas (Idso, 1992). Recently it was suggested that iron and sulfur cycles in
both the atmosphere and the ocean may be closely coupled (Zhuang et al., 1992).
Although the relationship between marine biological activity and the sulfur production rate
is not fully understood (Charlson et al., 1987), it is safe to assume that the net sulfur
emission to the atmosphere will be affected. For example, it was pointed out that sulfate
and methanesulfonic acid (MSA), the two oxidation products of dimethylsulphide (DMS),
both decreased in concentration during the transition from the last ice age to the present
interglacial, possibly because of the decrease in atmospheric dust loads and subsequent
reduction of iron delivery to the oceans (Idso, 1992). Furthermore, these authors pointed
out the strong dependence of cloud-condensation nuclei (CCN) formation over the oceans
on the dimethylsulphide production by the marine planktonic algae, and its importance on
the cloud albedo and climate.
3.2.4. The Volcanic Aerosols
In this section, after a short review about current knowledge, the overall
characteristics of the anomalous elemental enrichment episodes and their possible
relationship to volcanic emissions will be discussed. This will be followed by a discussion
of possible volcanic signatures in a group of specifically chosen samples from certain dates
with suspected or known volcanic activity (see section 2.1.1). Finally, a discussion about
the possibility of volcanic impact on a previously observed rare earth element (REE)
enrichment episode (Keskin et al., 1992) (see section 2.1.1) will be presented.
The impact of volcanic emissions on the total atmospheric aerosol budget has long
been recognized and became clearly evident after the recent volcanic eruptions of El
Chich6n (Mexico, 1982) and Mount Pinatubo (Philippines, 1991), whose effects were
extensively examined (e.g., Kotra et al., 1983; Woods et al., 1985; Wallace and Gerlach,
1994).
Depending on the type and strength, a volcanic eruption event can affect
atmospheric composition on a local, regional, or global scale (Buat-Menard, 1990).
Large-scale eruptions inject volcanic gases (mainly sulfur dioxide and halogenated acids)
and dust (generally silicate ash) into the stratosphere in which they often remain suspended
for several weeks to several years (Cadle et al., 1976). A major increase in atmospheric
dust content has a serious effect on the climate by changing the atmospheric albedo
(Rampino and Self, 1982). It is now believed that even small-scale eruptions disturb the
global budgets of sulfur and some volatile heavy metals and metalloids to a considerable
extent (Buat-M6nard, 1990). The determination of volcanic contributions is also needed
to accurately assess the anthropogenic contributions because the enrichment mechanism of
volatile elements on volcanic aerosols is similar to that occurring on anthropogenic
aerosols produced by high-temperature industrial activities (Buat-Menard, 1990).
As explained earlier, polar ice sheets contain and preserve atmospheric substances
in their strata by wet and dry deposition mechanisms. In recent years, many volcanic
eruption horizons identified in deposited ice layers were recognized by their high sulfate
concentrations (converted from sulfur dioxide) (see Moore et al., 1991; Dai et al., 1991;
Delmas, et al., 1992; Langway et al., 1994; Langway et al., 1995). However, possible
nonlinearities between the scale of an eruption and the amount of sulfur dioxide gas
released was recently pointed out (Bluth et al., 1993; Williams, 1995). Although trace
element compositions of volcanic plumes and ashes were determined for some volcanoes
(Phelan et al., 1982; Zoller et al., 1983; Phelan-Kotra, 1983; Olmez, et al., 1986; Kyle and
Meeker, 1990; Dunbar and Kyle, 1990), understanding of the trace element contribution
to the ice sheets from volcanic activity is still limited. Sampling results by these authors
showed that the elements fluorine, sulfur, chlorine, chromium, cobalt, copper, zinc,
arsenic, bromine, molybdenum, indium, antimony, cesium, tungsten, gold, mercury,
cadmium, iridium, and selenium are generally highly enriched in plume and ash samples.
However, it has been established that the composition of volcanic plumes can vary with
time even for the same volcano (Buat-M6nard, 1990), and this
complicates the
determination of a definite signature for a given volcano.
In the previous sections marine and crustal enrichment factors (EF) were examined
for the elements measured in this work. The results indicated that most of the elements
are mainly of crustal origin, while some others are mainly of marine origin. The remaining
group of elements that has high marine and crustal EF's should have additional sources.
These elements are chromium, zinc, arsenic, molybdenum, cadmium, and antimony.
However, as can be seen from Table A.1 in Appendix A, molybdenum, and cadmium have
low observation frequencies and high measurement uncertainties. Among the rest of the
enriched elements, antimony and arsenic show the distinct trend of decreasing crustal
enrichment factors, especially after the 1950's, in addition to their overall correlation
(Figures 3.14 and 3.15). This behavior rules out anthropogenic contribution as the main
source for these elements.
The most likely natural source category seems to be volcanic emissions, since it
was already mentioned that these elements are highly enriched in volcanic emission
plumes.
Also, no observed signature exists to indicate any significant extraterrestrial
contribution to the observed trends. Although the annual number of large-scale volcanic
eruptions seems constant throughout the last two centuries (Simkin, 1994), it is likely that
the early records are not complete and some of the eruptions at remote locations, such as
Antarctica, were missed. Therefore, more active volcanism (at least locally) could be
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elements (VME) in the rest of the discussions) in the pre-1950 era.
It should be mentioned that there are other elements (e.g., selenium, indium) highly
enriched in volcanic emission plumes that can be used as marker elements.
However,
some of these elements had near or below detection limit concentrations for the analytical
technique used in this work (INAA), and the number of measurement results with low
enough uncertainty levels were limited. Remember that in section 3.2.1 the Cl/Na ratio
was also found higher in the pre-1940 samples as a sign of possible larger volcanic
emission contribution to the annual chlorine concentration budget.
If the aluminum
concentration distribution is assumed uniform in an annual deposition sample (which is not
realistic), an approximate correction to the Nalq concentrations can be made so that Cliqto-(Nalq)X ratio can be calculated. This calculation gives 2.7±0.1 and 2.4+0.4 for pre- and
post-1940 periods, respectively, which do not seem very different. However, as explained
before, Cl, and Naiq concentrations were measured in very small samples which cannot
fully reflect the annual trends, and these results should be taken as informational values.
In spite of this uncertainty, ratios much higher than that of sea water (1.8) are likely to
indicate extra chlorine contribution from volcanic emissions.
Significant enrichment episodes of VME's were observed in six specific years in
this work. In addition, one of these episodes (1948) was followed by enrichments of rare
earth elements in the subsequent two years. The crustal Enrichment Factors (EF,) of these
enriched elements at the time of the observed signal are summarized in Table 3.5.
The first VME enrichment episode occurred at 1969 together with an enrichment
of Br. However, the marine Enrichment Factor (EFm) of Br is 0.9+0.2, which indicates a
marine source contribution.
The combination of these enrichments might indicate a
specific type of volcanism (submarine) of possible local origin.
Among the recorded
volcanic eruptions (Simkin et al., 1981) one possible candidate seems to be the 1969
eruption of Deception Island Volcano (62.93 S and 060.57 W) in Antarctica. This was
recorded as a "subglacial" and "explosive" eruption that indicates a sudden release of
water along with other gaseous and particulate material (Simkin et al., 1981).
The
volcanic explosivity index (VEI) (Newhall and Self, 1982) for this eruption was three
Table 3-5.
The crustal Enrichment Factors of the enriched elements in suspected
volcanic eruption horizons.
Date of
signal
[A.D.]
1949
1948
1940
1870
1822
1791
7950
46650
98150
31100
18900
23550
+1280
±28480
±36150
±9000
±3800
±9800
60
300
400
150
100
95
±15
+190
±150
±50
±25
±40
EF
1969
Sb
As
La
Ce
Sm
1950
20
91
±2
±15
19
88
±2
±14
13
63
±2
±11
which is a moderate to large scale emission with potential stratospheric injection. The
observed increase of Br and Na, concentrations, while their ratio is similar to that of the
sea water, might be due to the interaction of ejected hot material and the surrounding
ocean that might enhance marine aerosol production. Even though this volcano is quite
close to Byrd Station, no significant sulfate signal that coincides with this year was
observed in the ice core used in this work (NBY-89) (Langway et al., 1994). However, a
further examination of the data provided
by Langway and Osada (personal
communication) showed that there is approximately a three fold increase on the excess
sulfate (non sea-salt origin) for a short period during the 1969-70 transition that might
have originated from the Deception Island eruption. The observed delay in the occurrence
of the sulfate peak might be due to the time necessary for the sulfur dioxide-sulfuric acid
conversion and deposition processes.
Another observed signal that might be related to this eruption comes from an ice
core drilled in East Antarctica (G 15) in 1984 (Moore et al., 1991). The continuous
conductivity measurements on this 100 m long ice core revealed a very sharp peak that
coincided with the 1969-70 horizon. These authors suggested that the characteristic of
this peak points out a local non-stratospheric eruption, most likely the Deception Island
Volcano in the Antarctic Peninsula.
This conclusion is in good agreement with this
paper's conclusion, and the signal in 1969 is almost certainly come from the Deception
Island Volcano. The reason that this eruption was not observed in ice cores from the
Antarctic Peninsula, much closer to the eruption, was suggested to be related to the wind
patterns that transported the eruption plume to Antarctic ice sheets (Moore et al., 1991).
It was also mentioned that (Boutron, 1980) no other eruption occurred at
Deception Island between 1842 and 1967, except for five successive major eruptions
between 1912±5 and 1917±3, as revealed by the study of the successive pyroclastic
deposits in local ice (Orheim, 1972). Since only three samples were analyzed between
1907 and 1920 in this work (1907, 1913, 1919), and none of them showed any significant
signal, it is not possible from this work to understand whether the elemental compositions
of different eruptions are similar to each other or not.
One interesting result that is worth mention is the lack of any elemental enrichment
signal related to the prominent and well-recorded acidity signal of the Mount Agung
(08.342 S and 115.508 E) volcanic eruption (VEI=3) in 1963 (e.g., Moore et al., 1991;
Langway, Jr. et al., 1994). One explanation might be the distance of the eruption from the
central Antarctic ice sheets and the different transport properties of the gaseous and
particulate substances that eventually cause the acidity or elemental concentration
enhancements in the ice sheets. While it is more likely for gaseous sulfur dioxide to be
elevated up to the stratosphere and transported into the Antarctic atmosphere, it may not
be easy for particulate species to escape removal in the troposphere for a moderate to
large scale eruption.
The second VME enrichment episode was observed in 1948 followed by very high
REE enrichments in 1949 and 1950. In addition, the zinc enrichment was moderately high
during this three year period while the Br enrichment was moderately high in 1948.
Similar to the previous signature, the Br-to-Nas ratio (0.007+0.003) is close to that of sea
water (0.0062), which again might indicate a specific type of volcanism of local origin.
Among the recorded volcanic eruptions (Simkin et al., 1981), one possible candidate is
the 1947 eruption of the Mount Erebus Volcano (77.58 S and 167.17 E) in Antarctica.
This was recorded as an "explosive" eruption with lava flow (Simkin et al., 1981). The
volcanic explosivity index (VEI) for this eruption was two which is a moderate scale
eruption with no stratospheric injection. Similarly the observed increase of Br and Na,
while the Br-to- Na. ratio stayed close to that of sea water, might originate from the
interaction of ejected hot material and the surrounding ocean as explained before. The
highest enrichments of VME's and REE's were observed in 1948 and 1949, respectively
(Figures 3.14 and 3.16). This lag time in the peak enrichments might result from the
different physical properties of these elemental groups.
While the VME's are quite
volatile, this is not the case for REE's. Therefore, the release of volatile elements might
have begun earlier with non-explosive fumarolic activity, while that of the refractory
elements might have intensified only when the explosive eruptions started. However, one
cannot rule out the coincidence of two different events that follow each other. There is no
regular observational information regarding the volcanic activities in Antarctica prior to
1956 (Boutron, 1980) which makes it difficult to reach a final conclusion.
It was previously suggested that concentration ratios of certain elements, such as
REE's, in volcanic emission plumes might be used to characterize certain groups of
volcanoes (Palais and Mosher, 1989). However, the results of a study to characterize the
plume composition of the Mount Erebus Volcano (Kyle et al., 1990) indicated that the
elemental concentration ratios were not constant even on a day-to-day basis. Therefore, it
is not possible to make any concrete identification on the basis of the elemental
enrichments that coincided with this episode.
Although sulfate and conductivity
measurements did not indicate any significant signal for these years in the NBY-89 ice
core (Langway et al., 1994) and others from Antarctica (e.g., Moore, 1991; Delmas et al.,
1992), Mount Erebus Volcano cannot be ruled out as a candidate for this episode.
The third VME enrichment episode was observed in 1940.
This event is the
strongest and longest (1937-44) one in the continuous annual sampling period (19261989) of this work. In addition, chromium, bromine, sodium, and chlorine were also
enriched significantly. As mentioned in section 3.2.2, 1939-40 was the time of one of the
strongest El Nifio events in this century, and the observed sodium, chlorine, and bromine
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enrichments probably resulted from this event. One strong candidate for the observed
VME's peak is the 1937-43 eruptions of the Rabaul Volcano in Papua New Guinea
(04.271 S and 152.203 E). All were "explosive" eruptions with decreasing VEI's between
4 and 2 (Simkin et al., 1981). Although the distance from the Antarctic ice sheets is very
far, the strong scale and duration of eruptions with highly likely stratospheric impact could
allow aerosols from the eruptions to participate in long-range transport. In addition, the
coincidence of this event and 1939-40 El Nifio event might have increased the transport
efficiency of aerosols due to the changing atmospheric currents. As seen in Figure 3.14,
the 1940 enrichment peak is very sharp, while the others show more gradual behavior.
Moderate scale (VEI=3) 1938-40 eruptions of the Krakatau Volcano in Indonesia (06.102
S and 105.423 E) might have also contributed to this signal.
It is somewhat surprising for this scale eruption that no significant sulfate signal
was recorded in ice cores obtained from Antarctica (e.g., Moore, 1991; Delmas et al.,
1992, Langway et al., 1994) that coincide with these years.
However, it was already
pointed out that (Williams, 1995) sulfur dioxide released from the 1994 eruption of the
Rabaul Volcano was surprisingly low for its class (only 0.5 % of the 1991 Pinatubo
eruption), which might also be the case for 1937-43 eruptions.
The remaining VME episodes observed in 1870, 1822, and 1791 occur in the time
period (1711-1926) that has sparse data. Therefore, it is not possible to be sure whether
these signals show the year of peak deposition. The signal in 1870 might be part of the
signal from the listed 1871±40 eruption of the Deception Island Volcano dated by
tephrochronology (Simkin et al., 1981). However, no more information is available about
this eruption. No large scale (VEI 2 4) eruptions within the Southern Hemisphere are
listed around this date (Newhall and Self, 1982), and further comment on this signal is
difficult.
The signal in 1822, combined with the results of the analysis (Table C.2 in
Appendix C) of two other specifically chosen samples from 1819-20 and 1820-21 (see
section 2.1.1), indicates a possible volcanic event between 1820 and 1822. In a study to
characterize the morphological properties of microparticles recovered from a South Pole
ice core's suspected volcanic activity horizons (Palais et al., 1989), results showed good
agreement between microparticles from an approximately dated 1816-21 layer and tephra
known to be from Deception Island Volcano (Orheim, 1972). Therefore, it is likely that
this signal originated from another eruption of Deception Island Volcano. However, the
observed zinc enrichment is much higher than that of the 1969 signal.
Although no
significant sulfate signal is observed in Antarctic ice cores for this time, another potential
source listed in literature (Simkin et al., 1981) is the very large scale (VEI=5) 1822
eruption of the Galunggung Volcano in Java (07.25 S and 108.05 E).
The 1791 signal does not coincide with any recorded large scale volcanic activity
listed in the literature (Newhall and Self, 1982).
It probably originated from a local
volcano.
As mentioned at the beginning of this section, eight separate samples were selected
from certain dates with suspected volcanic activities (see section 2.1.1).
However,
because of the prior use of some of the samples that coincided with the exact dates of the
eruptions, samples closest to those dates were selected. The elemental concentrations
measured in these samples are given in Table C. 1 in Appendix C. Four of these samples
(1882-87) coincided with the eruptions of Krakatau Volcano in Indonesia (06.102 S and
105.423 E) and Tarawera Volcano in New Zealand (38.229 S and 176.508 E) in 1883-84
(VEI=6) and 1886 (VEI=5), respectively. The Krakatau eruption is universally observed
in both Antarctic and Greenland ice core sulfate and conductivity records (e.g., Delmas et
al., 1992; Crowley et al., 1993; Langway et al., 1994), while the Tarawera eruption signal
is resolved in some of the Antarctic ice core records (e.g., Moore et al., 1991).
The
sulfate peak caused by the Krakatau eruption was observed in the 1884 ice layer (21.6521.89 m) of the NBY-89 ice core (Langway et al., 1994).
Among the four samples
analyzed in this work, the sample from 1885 (21.53-21.70 m) shows the highest
enrichments for the elements arsenic, bromine, chromium, and zinc, while the sample from
1886 (21.38-21.53 m) shows the highest enrichments for the elements antimony and
cadmium.
Among these elements, zinc, bromine, and cadmium have the highest
enrichments observed among the more than one hundred samples analyzed in this work.
This indicates the impact of a very special event, possibly the Krakatau eruption. The
difference between the observance of a sulfate peak and elemental enrichment peaks is
related to the physical and chemical properties of aerosols and individual elements, as they
define the transport and deposition efficiencies. One interesting point is that the VME's
do not show unusually high enrichments as would be expected from eruptions of these
scales.
Another group of two samples (1819-21) was chosen from the years following the
eruption of Tambora Volcano in Lesser Sunda Island (08.25 S and 118.00 E) in 1815
(VEI=7, highest listed in the last five centuries). This eruption is also universally observed
in both Antarctic and Greenland ice core sulfate and conductivity records (e.g., Moore et
al., 1991; Delmas et al., 1992; Crowley et al., 1993; Langway et al., 1994). The sulfate
peak caused by this eruption was observed in the 1816 ice layer (28.50-28.90 m) of the
NBY-89 ice core (Langway et al., 1994). Among these two samples the 1819/20 sample
did not indicate any enrichment signal, possibly because of the four years passed after the
Tambora eruption.
However, the second sample from the 1820/21 layer showed
significantly higher enrichments than the first one. Possibly this signal is related to the
higher 1822 signal discussed previously.
The remaining two samples (1645-47) were chosen to coincide (as close as
possible) with an unknown sulfate signal observed in 1648 in the NBY-89 ice core
(Langway et al., 1994). These samples showed very high zinc but no significant VME
enrichments.
Therefore, it is difficult to claim a volcanic event from the elemental
concentrations obtained in this work.
As mentioned at the beginning of this section, in a preliminary study (Keskin et al,
1992) a specific REE enrichment signal was identified in a layer between 89.02 and 89.17
meter depths. Twelve more samples were obtained between the depths 88.15 and 89.51
meters continuously to locate the peak position of this signal (concentrations and EF's are
given in Table C.3 and C.4, respectively, in Appendix C).
The results indicated a
moderate enrichment of REE's and VME's in 1341 A.D. and 1340 A.D. respectively.
This signal is quite similar to that of the 1948 A.D. signal discussed earlier, except that the
scale of the enrichments are an order of magnitude smaller for both groups of elements.
Therefore, the local Mount Erebus Volcano might be a candidate for this signal.
3.2.5. The Anthropogenic Aerosols
As mentioned in the first chapter, one of the goals of this work was the
understanding of whether or not a detectable anthropogenic contribution to the elemental
concentrations levels found in Antarctica exists. The 278 year-long ice core record (1711
A.D.-1989 A.D.) obtained in this work is long enough to determine the average preindustrial and modem era elemental concentration levels for comparison. However, one
complication to this characterization comes from the contribution of volcanic emissions,
whose enrichment mechanisms of volatile elements on released aerosols are similar to that
occurring on anthropogenic aerosols produced by high-temperature industrial activities
(Buat-M6nard, 1990). Therefore, an accurate determination of volcanic contribution to
the total concentrations observed is an important and necessary task. Unfortunately, this
task is not easy as volcanic contributions are sporadic in nature, different in strength, and
inhomogeneous in aerosol composition. Another complication is the lack of information
about the stability of weather patterns throughout the last three centuries as they affect the
transport of aerosols from continental areas to the Antarctic ice sheets.
In a simple way, the time-series trends of the excess elemental concentrations that
are assumed to come from volcanic and anthropogenic sources can be obtained by
subtracting the crustal and marine contributions from the measured concentrations. For
this purpose, crustal and marine contributions were calculated by using the standard
concentration ratio of the element of interest to aluminum in crust (Taylor, 1972) and seasalt sodium (Na.) in sea-water (Goldberg, 1963). The resulting concentrations should
show the contribution from volcanic and anthropogenic emissions in an approximate
manner. Among the elements examined, arsenic, zinc, and chromium, which are known to
be enriched in emissions both from volcanic and anthropogenic sources seem to deserve
further discussion.
As seen in Figure 3.17 antimony concentrations show a decreasing trend after the
1950's, which was assumed in Section 3.2.4 to indicate the decreasing impact of volcanic
emissions.
However, the excess
(crustal and marine contribution corrected)
concentrations of arsenic do not show a significant change (Figure 3.18). Since arsenic is
also one of the marker elements used to characterize volcanic emissions, it is expected that
it would also show a decreasing trend. Therefore, in a qualitative sense this behavior
indicates an increasing anthropogenic contribution after the 1950's, which is possibly the
beginning of large scale industrial activities in the Southern Hemisphere. Increasing
concentration trends are somewhat more apparent for zinc and chromium in recent years
(Figures 3.19 and 3.20). Using the same argument, these trends are likely the result of
increasing anthropogenic emissions. To get an approximate quantitative sense about these
trends, the average concentrations were calculated in three time periods (1711-1901,
1907-1950, 1951-1989), and percent changes relative to the 1711-1901 time period were
calculated (Table 3.6). In these calculations, the years with unusual episodic behavior
were eliminated.
Table 3-6. Percent average concentration changes for Sb, As, Zn, and Cr
relative to the 1711-1901 time period.
Element 1907-1950
1951-1989
Years ignored
Sb
+31
-47
1822, 1870, 1940
As
+80
+45
1822, 1870, 1940, 1944, 1945
Zn
-32
+28
1799, 1822, 1949, 1950, 1951, 1985
Cr
+28
+155
1939, 1940, 1970, 1979
In a recent study, lead, cadmium, copper, and zinc concentrations were measured
(Gbrlach and Boutron, 1992), and no significant increase was observed between 1940 and
1980 with the possible exception of lead for which a significant increase seems to have
taken place after the mid 1960's in Antarctic snow samples from Adelie Land, East
Antarctica. However, since the rate of change is likely to be less within this time interval
compared to that of the time interval examined in this work, it might have been more
difficult to observe any possible change. Otherwise, some increase in the concentrations
of anthropogenic elements is expected even if on a very small scale. Among the
anthropogenic source regions of the Southern Hemisphere, the coast of Peru was
identified as a substantial source of copper, zinc, arsenic, and lead concentrations that are
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thought to be related to the large emissions of the extensive mining and smelting industries
in that region (Raemdonck et al., 1986). In addition, human activities in manned scientific
research stations in Antarctica are suspected to be an additional source for some elements
in recent years (Boutron and Wolff, 1989).
An attempt has been made to calculate the approximate natural background
elemental concentration levels within the pre-industrial (1711-1901) era. These values
were obtained from the frequency distributions of the elemental concentrations within this
era. The most probable values of the distribution curves were chosen as the background
values due to the reasons explained in section 3.3 and the results are given in Table 3.7.
Table 3-7. Calculated natural background concentrations.
Element
Concentration
Element
Concentration
[ng/g-ice]
3.3.
Na
Mg
Al
Cl
K
Sc
Ti
V
23
2.4
4.4
50
2.2
0.0001
1.0
0.01
Cr
0.23
[ng/g-ice]
Mn
Fe
Zn
As
Br
Sb
La
Ce
0.05
3.6
0.9
0.001
0.009
0.019
0.001
0.001
Source Characterization
3.3.1. Source-Receptor Relationship
One can define aerosol production, transport, and deposition mechanisms as part
of an integral system. A simplified overall picture of this system can be given, as in Figure
3.21. Here, the receptor site is the location of sample collection, and the sources are
continental regions, oceans, volcanoes, and possible others. The transfer functions contain
information about factors that affect the transport of aerosols from production sites to the
deposition site. Some of these factors are transport distance, wind trajectory, transport
altitude, and chemical / physical processes. For example, as discussed in section 3.2.1,
marine aerosols released from the oceans may not have the same composition when they
arrive at the deposition site after a long transport because of the loss of chlorine due to
some chemical reactions during the transport. Another example is the size segregation of
aerosols during long-range transport that might change the original aerosol composition,
since some elements are preferentially contained in smaller or larger aerosols. However,
knowledge about these transfer functions is far from complete due to the unpredictability
of atmospheric processes or a lack of understanding about some mechanisms. In addition,
knowledge about these sources, their strengths and compositions is also limited, since the
system covers almost all of the Southern Hemisphere and, in some cases, the whole globe
as possible source regions. Therefore, the only other alternative for identifying sources
with a significant contribution to the aerosol composition in Antarctica is to use
multivariate statistical analysis techniques, such as Principal Component Factor Analysis.
Transfer function 1
Transfer function 2
Figure 3-21.
Schematic of source-receptor relationship.
3.3.2. Principal Component Factor Analysis
Principal Component Factor Analysis (PCFA) is a multivariate statistical analysis
technique for the interpretation of large data sets. Today this and similar techniques are
increasingly being used in environmental sciences (e.g.,Okamoto et al., 1990; Artaxo et
al., 1992; Olmez et al., 1994), as well as other branches of science. Part of this increase is
due to the availability of fast measurement techniques for obtaining large data sets and the
advancement of computational power within the last few decades.
The PCFA is
performed to identify possible correlations among variables of a data set, and its success
is closely dependent upon the number and accuracy of observations of the variables. In
this work, the variables are the elements, and the observations are the annual average
concentration measurements of them. The mathematical background of this technique is
given in Appendix D.
The PCFA was applied to 97 individual concentration measurement results for 14
elements. Prior to the analysis, the summary statistics for each element were obtained
from Statgraphics TM version 6.1 statistical analysis package, and these results are given in
Table A.2 in Appendix A. The first consideration was the treatment of missing values for
some elements with concentrations close to the analytical detection limits. Since the
success of the PCFA technique depends on the completeness and accuracy of a data set,
this step was necessary before starting the analysis. For this purpose, the number of
missing values for each element was determined from the summary statistics, and only
elements with less than 25 % missing data were accepted for the analysis. In addition,
elements with high uncertainties were excluded from the analysis. The first step in the
treatment of missing values was the determination of the frequency distribution
characteristics of the measured elemental concentrations.
Results showed that the
frequency distribution function for each element is close to logarithmic. This behavior is
expected since most of the time concentration values should be close to background
values due to dilution effect, and higher values should be observed only due to the specific
contributions from various sources for limited durations (Ott, 1990). The next step was to
find the most probable concentration values for each element to replace the missing
values. They were obtained from the frequency distribution curves and are given in Table
A.5 in Appendix A.
After the treatment of missing values, the raw data matrix containing elemental
concentration values for 97 samples, was entered into the factor analysis program within
the statistical analysis package Statgraphics TM version 6.1. The necessary options were
chosen to standardize the data matrix, not to change the diagonal elements of the
correlation matrix with the estimated communalities (principal components analysis), and
to rotate the factor matrix using the varimax method. The mathematical details of these
options are explained in Appendix D. After the first run, factor scores were plotted for
each factor, and samples with factor scores above six (standardized factor score value)
were excluded in the next run. Note that the factor score of a sample for a specific factor
represents the relative contribution of that factor (source) to the sample.
Since the
standardized factor scores were determined by subtracting the average value from each
raw score, and dividing the difference by the standard deviation of the scores, a sample
with a factor score greater than six would be affected six standard deviations more than
the average sample. However, since this kind of impact should result from a very specific
and rare event, exclusion of these extremes is preferred to prevent their dominance on the
overall analysis. Otherwise, this could affect the factor loadings and cause bias for the
overall correlations of the elements in a group. After this sample exclusion step (only
sample # 11IC5 was excluded), the new data matrix was entered into the program, and the
new results were analyzed in the same fashion. Since the new set of factor scores were
below the predefined limit six (Figures 3.22-3.25), the factor loading results were
accepted as the final values. Note that the standardized factor scores have the average
value of zero, and the negative scores show less than average relative contribution of the
associated factor to the related samples.
The final factor analysis results are summarized in Tables 3.7 and 3.8. Table 3.7
contains the communalities for each element, eigenvalues for each factor (source), percent
variance explained by each factor, and the cumulative percent variance. As can be seen,
four factors have eigenvalues above unity and they explain 63.1% of the variance in the
data set. As discussed in Appendix D, factors with eigenvalues below unity (average
value) are generally assumed to result from errors in the data set. Using the first four
factors, the varimax rotated (see Appendix D) factor loadings matrix in Table 3.8 was
obtained. Factor loadings with values above 0.3 were assumed significant and retained.
The elements in a factor with loadings above this value were considered to be coming
from a common source. Although no clear rule for determination of this cut point exists,
values between 0.25 and 0.50 were used in the literature for different applications (Olmez
et al., 1994).
Table 3-8. Factor analysis results for related parameters.
Element
Na
Al
Cl
K
Sc
Cr
Mn
Fe
Zn
As
Br
Sb
La
Sm
Communality
0.68
0.58
0.69
0.31
0.63
0.52
0.41
0.45
0.39
0.30
0.24
0.37
0.59
0.54
Factor No
Eigenvalue
1
2
3
4
5
6
7
8
9
10
11
12
13
14
4.23
1.95
1.53
1.12
0.92
0.81
0.73
0.68
0.57
0.51
0.33
0.23
0.21
0.17
%variance
%cumulative of
explained
explained variance
30.2
13.9
11.0
8.0
6.6
5.8
5.2
4.9
4.1
3.7
2.4
1.7
1.5
1.2
30.2
44.1
55.1
63.1
69.6
75.4
80.6
85.5
89.6
93.2
95.6
97.3
98.8
100.0
The elements aluminum, potassium, scandium, zinc, lanthanum, and samarium are
grouped together in the first factor, which explains the most variance of the data set. The
other factors follow the first one in decreasing order of importance for explaining the
variance. These elements are known to exist in crustal aerosols, and this factor implies a
crustal source for the observed concentrations of these elements. As discussed in section
3.2.3, the arid regions of Australia and South America are the likely candidates for the
crustal aerosol input into the Antarctic continent.
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104
o
II
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C'4
The second factor shows sodium, chlorine, potassium, and chromium grouped
together. The first three elements clearly indicate a marine aerosol impact on the observed
elemental concentrations.
Considering that Antarctica is surrounded by oceans, it is
certain that these oceans are the sources for these elements. Although chromium is not
enriched in the bulk of ocean water, its enrichment in the ocean surface microlayer and
attachment to sea-salt aerosols is a possibility.
Table 3-9. Factor loadings (after varimax rotation) and estimated communalities.
Element
Estimated
Factor No Factor No Factor No Factor No
communality
1
2
3
4
Na
Al
Cl
K
Sc
Cr
Mn
Fe
Zn
As
Br
Sb
La
Sm
0.72
0.69
0.84
0.56
0.70
0.59
0.57
0.59
0.48
0.63
0.37
0.69
0.78
0.62
0.77
-
0.52
-
0.91
0.62
-
0.37
0.74
-
0.64
-
-
-
-
-
0.53
-
-
-
-
-
-
-
0.86
0.76
0.64
-
-
0.31
0.40
0.74
0.70
-
0.49
-
0.42
0.79
0.36
0.82
-
-
-
The third factor has significant loadings of manganese, iron, aluminum, and
moderate loadings of bromine, chromium, and scandium.
Although most of these
elements are known to be mainly crustal in origin, the coexistence of bromine, which is
known to exist mainly in sea water is interesting. In recent years, an almost a near-total
depletion of the surface level ozone has been observed in the Arctic spring, coincident
with high atmospheric concentrations of inorganic bromine (Fan and Jacob, 1992). It was
previously suggested that the ozone depletion could be due to a catalytic cycle involving
the radicals Br and BrO (Barrie et al., 1988). This gas phase catalytic cycle is given as,
105
Br + 03 * BrO + 0 2
BrO + BrO -- 2Br + 02
(i)
However, bromine is quickly converted to HBr, HOBr, BrNO3, and other brominated
organic compounds (BOC) by gas phase reactions with species such as HO 2 and HCHO.
Therefore, the ozone destruction cycle would quickly be terminated (Fan and Jacob,
1992). Recently, it was proposed that the HBr and BOC's could be scavenged by the
ambient aerosols and ice crystals, and Br 2 could be released back through heterogeneous
reactions on these particles' surfaces (McConnell et al., 1992). Therefore, this cycling
would maintain sufficiently high levels of Br atoms and BrO radicals in the ambient air for
ozone destruction. These authors suggested that Br might be formed by the photolysis of
Br 2(g), which in turn can be formed by the conversion of sea-salt derived Br- through
photoactivated reactions on aerosols and snow-packed surfaces. In the past, a possible
mechanism for this conversion was suggested as (Duce et al., 1965),
4Br- + 02 + 4H++ hv -+ 2Br 2 + 2H 20
(ii)
Although the detailed sequence of the reaction (2) is not known, one of the suggested
mechanisms was given as (Carey and Langford, 1975),
Mn+Br
Br
- 400nm
M (n-1)+++ Br"
2 Br' -- Br 2
2M
(n- l ) +
102+ H+ -- 2M n + + OH-
2
(iii
where, M is a transition metal such as Fe(III), Mn(IV), or Cu(II).
In light of this information, the third factor that was mentioned before suggests a
similar transition metal catalyzed bromine production mechanism, and possible subsequent
ozone destruction in the Antarctic surface level ambient air. Since the aerosols and ice
crystals are eventually deposited onto the surface snow layers, these possibly crustal origin
106
aerosols could also cause the deposition of some bromine together with some transition
metals. Therefore, the elements manganese and iron, which are grouped with bromine,
seem to be good candidates for the catalytic reaction (3). Since copper was not measured
in this work, it is not possible to comment on it. The possible crustal origin of these
aerosols might explain the existence of aluminum and scandium in this group. These
conclusions are partly supported by another study on South Pole aerosols (Tuncel and
Zoller, 1995) as it was found that particles reaching the South Pole during summer are
enriched in bromine, while no enrichment appears in the winter. This would require the
availability of a gaseous bromine reservoir during summer, which possibly could result
from the proposed reaction (3). In addition, these authors observed bromine in a factor
that also included manganese and iron. However, one difference comes from the
observation of moderate bromine loading in another factor with sodium and chlorine
(marine factor) in the South Pole aerosols study while its additional occurrence is in the
volcanic factor in this work. The reason for this difference is not clear at this time.
The fourth factor contains the elements antimony, arsenic, bromine, and zinc. As
mentioned in section 3.2.4, these elements are highly enriched in volcanic emission plumes
and are probably of volcanic origin. A similar factor for the elements antimony, arsenic,
and zinc was found in the South Pole aerosol study and was also suggested to be volcanic
origin (Tuncel and Zoller, 1995).
3.4.
Air/Snow Partitioning
3.4.1. Current State of Knowledge
To this point, a clear distinction has not been made regarding the relationship
between the elemental concentrations measured in snow deposits and the ambient
atmospheric aerosol concentrations. To understand this relationship better, the details of
the aerosol air/snow partitioning processes should be examined. The importance of
making an accurate determination of the ambient aerosol concentrations stems from the
107
fact that aerosols have an important place in the radiation balance of the earth/atmosphere
system (Pyle, et. al., 1988). Aerosols affect the radiation balance both through direct
interaction with incoming solar, and outgoing infrared radiation, and by indirect effects
due to their role in cloud formation processes. A direct effect of ambient aerosols on
surface radiation flux is caused by scattering, absorption, and emission processes.
However, the major effect of aerosols in the atmosphere is on cloud optical properties
through the cloud condensation nucleation processes (CCN), which in turn affect the
cloud/radiation interaction through changes in the drop-size spectrum, cloud lifetime,
cloud albedo, and in-cloud absorption (Ghan et al., 1990; Preining, 1991). The
cloud/radiation interaction was specified (Grassl, 1988) as one of the most important
processes in the climate system. It has been shown that the magnitude of the global cloud
albedo effect could be of the same order as the greenhouse effect on increased
carbondioxide (Twomey et al., 1984). Therefore, an accurate radiation budget calculation
depends strongly on the determination of aerosol characteristics such as number density,
size distribution, and chemical composition. Radiation balance and general circulation
climate models should be tested for past climatic changes to rely on their future
predictions. Because Antarctica is the largest sink for energy in the natural global system,
it plays a very important role in determining the climate balance over a large part of the
earth's surface (Simmonds, 1990).
Any serious feedback mechanism, such as cloud
albedo forcing, must be treated accurately for realistic predictions.
It is therefore
important to reconstruct the aerosol composition and number densities in past
atmospheres to be able to use them in these models.
A short review about the characteristics of polar atmosphere aerosols and
deposition mechanisms might be useful to understand the air/snow fractionation processes.
A more comprehensive topical discussion can be found in the literature (e.g., Junge, 1977;
Shaw, 1980; Davidson, 1989).
Aerosol size characterization studies showed that a bimodal size distribution exists
over the Antarctic ice sheets. Using multiwavelength optical measurements (Shaw, 1980),
the small and large modal diameters were found to be < 0.1 pLm and 0.28 ± 0.04 ptm,
108
respectively. Results of the same work showed that the particle number concentration at
inland sites is dominated (96 %) by the small mode while particle mass is dominated (99.8
%) by the large mode. In another study (Dick, 1990), these bimodal sizes were found to
be larger for the Antarctic peninsula region which is close to the oceans and affected by
the large sea-salt aerosols.
However, the South Pole measurements are more
representative of inland regions like Byrd Station.
Sulfur was found to be the main
component (70-80%) of the Antarctic ice sheet aerosol mass (Cunningham and Zoller,
1981; Wagenbach et al., 1988). It is concentrated mainly in the Aitken particles (- 0.01
gtm diameter) and the accumulation mode particles (-0.1 to 1 Jtm diameters), which are
formed by the coagulation of Aitken particles due to Brownian motion. It is believed that
these Aitken particles are formed by gas-to-particle conversion of sulfur containing trace
gases that are released from oceans and industrial activities (Shaw, 1989). The lifetime of
these particles is only a few days because of coagulation, hence, these particles are
thought to be produced in situ over the ice sheet. Marine and crustal aerosols are found
mainly in the large mode; their properties were discussed previously in sections 3.2.1 and
3.2.3, respectively. The crustal aerosols play an especially important role in the ice phase
nucleation process in the Antarctic atmosphere in spite of their small mass fraction (- 5%).
It has been shown that the most common nuclei for snowflakes are clay minerals
originating from crustal source regions (Kumai, 1976), and also that crustal aerosol is
removed more efficiently than other aerosols (Cunningham and Zoller, 1981; Boutron,
1982). These ice nuclei generally satisfy the requirements of insolubility in water, are
large, have chemical bonding and crystallographic structures similar to those of ice, and
have certain topographic surface features (Hobbs, 1993).
The aerosol deposition mechanisms are classified into two main groups as the dry
deposition and wet deposition mechanisms.
Dry deposition of aerosols onto the snow
surface includes gravitational settling, impaction, and diffusion mechanisms which proceed
regardless of the existence of precipitation. Among all processes, gravitational settling is
the most effective for large particles (> 20 jtm diameter) while diffusion is the most
effective process for small particles (< 0.1
itm) (Seinfeld, 1986); impaction affects the
109
particles with diameters larger than 0.1 ýtm (Davidson, 1989).
Wet deposition
mechanisms are separated into two main groups as the in-cloud and below-cloud
scavenging mechanisms (Junge, 1977).
In-cloud scavenging processes include cloud
droplet nucleation, ice crystal nucleation, interstitial aerosol uptake, and riming of cloud
droplets. The below-cloud scavenging processes include sweeping of aerosols by falling
snow crystals by impaction and diffusion.
Among the various aerosol deposition mechanisms, the dry deposition and belowcloud scavenging mechanisms are comparatively better understood and mathematical
models for these mechanisms have been developed (e.g., Junge, 1977; Ibrahim et al.,
1983; Noll and Fang, 1989; Dick, 1990; Frank et al., 1990; Miller and Wang, 1991).
Recently an increasing number of modeling efforts have been made for in-cloud processes
(e.g., Flossmann, 1991; B6hm, 1992; Tlisov et al., 1992; Qin, 1992; Schulist and Freeman,
1992), but success has been limited. Significantly, it has been observed and reported
(Shaw, 1980) that the in-cloud nucleation mechanism is responsible for more than 90% of
the total aerosol mass deposited onto the Antarctic ice sheets, and dominates the removal
of all particles from the atmosphere with diameters from about 0.2 to 10 .tm (Junge,
1977).
Another model study (Dick, 1990) revealed that wet deposition processes are
responsible for removing more than 95% of the total atmospheric aerosols having
diameters between 0.3 and 2 km.
In summary, the apparent domination of aerosol deposition by in-cloud nucleation
mechanisms, and the lack of satisfactory understanding of these mechanisms so far
prevented the development of successful theoretical air/snow partitioning models.
However, it has already been suggested that when in-cloud nucleation processes
overwhelmingly dominate the removal of the significant mass of aerosols and aerosols are
well mixed and homogenized over the inland ice sheets, the elements with common origin
(e.g., crustal, marine) are expected to have similar scavenging ratios, and the chemistry of
ice layers should reasonably reflect the composition of the atmosphere at the time of
deposition (Junge, 1977). In other words, if crustal aerosols are taken as an example,
since they favor nucleation more than other kinds of aerosols (Kumai, 1976), the elements
110
having a predominant crustal origin should show similar scavenging ratios.
This
expectation was supported by an early work that in the existing clean air conditions in
central parts of the Antarctic ice sheet, the chemical composition of precipitation (Boutron
and Lorius, 1979) and aerosols (Maenhout et al., 1979) were reasonably interrelated
(Davidson et al., 1981) in contrast to what is observed in the sub-polar regions, in locales
such as Alaska (Rahn and McCaffrey, 1979).
The word "reasonably" is always necessary since there are inherent uncertainties
related to these processes. As an example, alteration of particle composition after initial
production by slow evaporation of volatile components or by the condensation of trace
gases onto the particles during transport or fallout can occur (Shaw, 1979). The degree of
these impacts depends upon the particle surface area and, thus, the particle size. At the
same time, the nucleation mechanism operates more efficiently on the larger particles due
to the lower Gibbs free energy, and thus higher thermodynamic stability of the solid-liquidvapor interface, and consequently preferential selection and removal of the larger aerosols
(Fletcher, 1958).
A slightly different crustal aerosol size distribution in the snow and
ambient air might result in a difference in the scavenging ratios because of the mentioned
alterations.
Other factors that complicate the air/snow partitioning include variety of
nucleation modes and the rimming of supercooled cloud droplets onto the ice particles.
Cloud droplet and ice nucleation mechanisms are the two major nucleation processes
which are effective in clouds (Barrie, 1985). Cloud droplet nucleation occurs more readily
on soluble components such as sulfate and marine aerosols, and does not lead to aerosol
removal by itself whereas ice nucleation occurs more readily on insoluble crustal aerosols
and causes aerosol removal by precipitation. Additional mechanisms include freezing of
supercooled water by contact-freezing and immersion-freezing nuclei, direct formation
from the vapor on deposition nuclei, and freezing of condensing droplets by condensationfreezing nuclei (Beard, 1992). Under certain conditions large snow crystals (> 200 jim
diameter) scavenge supercooled cloud droplets (2 to 50 ýjm in diameter) by inertial
impaction and interception as they fall past the small drops (Barrie, 1985). These cloud
111
droplets freeze upon contact with the snow crystals, a process called riming. Riming is
more likely to happen in warm clouds which permit a large number of cloud droplets to
form. Since the substances in cloud droplets are deposited onto the snow crystal surfaces,
concentration levels for rimed snow are higher than those of the unrimed snow crystals
(Davidson et al., 1987).
Contributions from the riming process to the elemental
concentrations measured in deposited snows should be less in central parts of an ice sheet
(Hammer, 1985) due to the absence of adequate moisture for supercooled cloud water
droplets to coexist in the cold clouds of inland ice sheets.
3.4.2. Scavenging Ratios
Calculation of the elemental scavenging ratios was made using the following
dimensionless equation:
W =CsPa
Ca
(3.5)
where Cs, Ca, and pa designate elemental concentration in snow [ng/g-ice], elemental
concentration in air [ng/m 3-air], and air density [g-air/m 3-air] (1440 at -28 Coand 1 atm),
respectively.
Since ambient elemental concentration data representative of the annual
average at Byrd Station, Antarctica is not available, data from the South Pole Station was
used (Tuncel et al., 1989; Tuncel and Zoller, 1995). The distance between these locations
is about 1000 km and a uniform aerosol distribution over the central ice sheets, as
discussed in chapter 1, is the basis for the use of South Pole ambient air elemental
concentrations. The South Pole data covers the period between 1979 and 1983. Annual
concentrations were obtained by averaging the summer and winter concentration
measurements. The scavenging ratios calculated from these ambient air measurements and
the ice core measurements (this work) are given in Table 3.9 for some of the elements
with the best available measurement accuracy. However, uncertainty levels are still high;
the major contribution to the final uncertainties came from the ambient aerosol
112
measurements, due to the low aerosol mass loadings in clean air conditions in central
Antarctica. Note that the aerosol samples were collected at surface level, and it is known
that the near-surface removal processes can deplete aerosol mass loadings in the turbulent
boundary layer (few hundred meters) (Shaw, 1979). This could create a systematic error
in the calculated scavenging ratios.
However, the relative difference between the
scavenging efficiencies of various aerosol categories should not be affected significantly.
Table 3-10. Air-to-snow scavenging ratios for some elements.
1979
1980
1981
1982
1983
Al
25750±21800
42000±24800
47900±24300
72150±41000
37500±27250
Fe
20000±15150
33800±19850
22100±13350
42000±27750
44800±31000
La
6250±8050
12150-9450
17900±14200
7050±5050
13900±9700
Na
8250±6200
8400±3000
7200±7850
5200±3300
3350±3850
Zn
5400±3600
3350±2700
11600±7450
15300±14600
55250±52200
Sb
1950±2400
16000±12400
10750±12300
11700±17000
31300±26300
As
350±250
700±350
2350±1900
1450±900
2750±2400
As shown in Figure 3.26, the scavenging ratios for aluminum and iron (mainly
crustal origin elements) are the highest listed and in agreement within the data
uncertainties, confirming the more efficient removal of crustal aerosols as discussed in the
previous section.
Although the earth's crust is the major source for the rare earth
elements (REE) in the ambient aerosol, the scavenging ratio of lanthanum was found to be
smaller (with high uncertainty) than that of other crustal origin elements. This seems to
result from experimental problems since a significant contribution of REE from other
sources, whose aerosols are not scavenged as efficiently, is unlikely in the Antarctic
atmosphere.
The element sodium (mainly marine origin) has lower scavenging ratios,
which is thought to be related in part to its high solubility in cloud water as discussed in
the previous section. The more volatile elements arsenic and antimony have the lowest
scavenging ratios in general, even though uncertainties are too high to be sure. This might
113
be due to their probable association with very small sized aerosols, which are not efficient
for nucleation removal.
In summary, the results showed that scavenging ratios can be used to reconstruct
the past ambient elemental concentrations in the atmosphere in an approximate way, and
in turn, these elemental concentrations can be used to find the number concentrations of
crustal, marine, and smaller size aerosols in the Antarctic atmosphere, assuming the
aerosol size spectrum has not changed considerably throughout this reconstruction period.
However, there are some drawbacks to this empirical approach. First of all the overall
uncertainty levels are far from satisfactory and should be reduced by more detailed and
longer duration aerosol sampling and analysis programs. Second, regional differences are
not treated in this approach, which could be quite important, especially for locations near
the ocean. Therefore, individual scavenging ratios should be obtained for regions within
Antarctica that have different geographic and atmospheric properties. Finally, the possible
seasonal differences on the scavenging ratios might be identified and treated for further
refining of this approach. The impact of seasonal differences was shown in Greenland
(Davidson and Honrath, 1987).
It might also be important for the warmer sites of
Antarctica due to the riming process as mentioned in the previous section.
114
_ C .
o
c
ilL:I
-o
<
CD
cON
0)
co
CVJ
ed
ed
L4
co
0)
0)
0
9-c
(D
CV
0 0
0 0(D
-000
00000000
0
0
0ý00 Pý D,Uý4 CI), C
115
0
0
Na
0)
CO
-
3.5.
Air Content Analysis
The results of the air content measurements in ice samples, including artificial ice
blanks, are given in Table 3.10. Here, samples and blanks were designated by the letters S
and B, respectively, and uncertainties were given as 1 values from the spectrum analysis.
As explained in section 2.3, artificially produced air-free ice samples were used to
determine the experimental uncertainty due to sample preparation and analysis steps.
Table 3-11. Air content measurement results for samples and blanks.
Sample ID
Depth Interval [m]
Weight [g]
Air Content [ml/kg]
B1
3.4
4.6 ± 1.1
B2
3.4
3.5 ± 1.0
B3
2.3
3.7 ± 1.1
B4
2.6
2.5 + 1.1
B5
2.5
5.7 ± 1.1
B6
3.0
5.6 ± 1.0
S1
101.20 - 101.22
3.6
46 ± 1.3
S2
101.20 - 101.22
3.6
49 ± 1.4
S3
101.20 - 101.22
3.1
43 ± 1.2
S4
101.22 - 101.24
3.8
37 ± 1.1
S5
101.22 - 101.24
2.2
39 ± 1.3
S6
101.50 - 101.52
2.0
39 + 1.3
S7
101.52 - 101.54
2.1
48 ± 1.4
S8
101.54 - 101.56
1.6
37 ± 1.3
S9
101.56 - 101.58
3.6
50 + 1.4
Although the blank samples were assumed to be air-free, in reality some amount of
air would have been left dissolved in the water prior to freezing. However, since it is
difficult to know the exact amount of the remaining air in the blank samples, the amount of
air measured (average 4.3 ± 1.3 ml/kg) was assumed (conservatively) to be the result of
external contributions due to the experimental stages. Considering that the average air
116
content in a Greenland ice core has been measured to be greater than 100 ± 5 ml/kg
between 100 and 1300 m depths (Herron, 1982b), the maximum uncertainty due to
experimental handling would be under five percent.
The air contents measured in real samples from the NBY-89 ice core showed good
agreement within each of the two same-depth layers. Samples from the first layer (S1, S2,
S3) and second layer (S4, S5) gave average air content values of 46 ± 3 ml/kg and 38 ± 1
ml/kg, respectively. The analytical uncertainties of these measurements are quite low due
to the very sharp and interference free Ar gamma-ray peaks observed for these samples.
Samples from the adjacent depth levels within an annual accumulation layer (S6,
S7, S8, S9) showed larger deviation (44 ± 7 ml/kg) compared to the samples from the
same-depth layers. This difference is probably the result of seasonal impact on the air
content. It has been shown that seasonal variations in air content can be as high as 25 %
in high accumulation areas, and this variation has been attributed to the sealing effect on
the summer layers by the denser winter layers (Martinerie et al., 1992). As a result,
summer layers have higher porosity than winter layers. In addition, wind and sunlight can
form thin, dense layers on the snow surface, which can also cause the isolation of the
previous layers within an annual accumulation layer. However, for deep ice cores with
annual layer thicknesses of a few centimeters, these seasonal variations become less
important.
It has been shown that the air composition in the bubbles of temperate glaciers can
change slightly if some melting occurs (Horibe et al., 1985). This type of melting can
happen especially in deep layers due to the high pressure applied by upper layers. These
authors observed a slight increase (around 1 %)in the N2/Ar ratio in the air extracted from
bubbles in deep ice samples from the Camp Century, Greenland, ice core. They suggested
that the higher solubility of argon in melted water and the subsequent push of this melted
water into the inter-granular layers between the ice (due to thawing of ice and bubble
pressure) could create this difference. Since the argon content of the ice samples was used
to find the air content of them in this work, this phenomenon could potentially have an
effect on the results. However, this difference of 1 %is negligible compared to the total
measurement uncertainties in this work. In addition, this method measures total argon
117
content (dissolved and undissolved), and unless the melted water migrated distances more
than a few percent of the core diameter, this phenomenon would not effect the results.
In summary, this new method for direct air content measurement in ice samples
might play a useful role in future ice core research, and additional work to develop the
method further is justified.
118
4.
SUMMARY AND SUGGESTIONS FOR FUTURE WORK
4.1.
Summary
The polar ice sheets contain a wide range of paleodata entrapped in stratigraphic
layers. They contain records of changing climatic conditions, deposits of atmospheric
constituents, and are sinks for atmospheric trace elements and other chemical species
which are transported by wind systems from various global sources.
In this study, snow strata that cover 278 years (1711 AD to 1989 AD) were
investigated to observe whether or not there is a significant difference in the Antarctic ice
sheet elemental concentrations due to anthropogenic impact. In addition, within this timeperiod there have been significant natural events, such as volcanic emissions and variations
in global air-mass movements, which could affect the elemental composition of the
atmosphere, and which could be investigated using trace element patterns.
Even though there have been previous studies to determine the trace element
concentrations in polar ice sheets, most have involved the measurements of a relatively
small number of trace element over discontinuous time-intervals. They were also limited
by the specific earlier analytical techniques used, the physical quality of the firn or ice core
samples used, and an evident lack of a close interdisciplinary and multiparameter approach
to an integrated study program. Of great importance, most of the previous data available
prior to this investigation are not continuous over long time-periods. However, since
changes in chemical composition trends in the atmosphere are extremely slow, detecting
these changes requires long records. The results of this study will hopefully fill an existing
gap in our knowledge.
An auxiliary goal was to develop a new method for measuring the air content in
very small ice samples from deep ice cores as it would be useful to study the relationship
between both the flow patterns and air content changes of glacier ice with depth (as well
as for dating purposes).
119
The Instrumental Neutron Activation Analysis (INAA) technique was used to
measure the elemental concentrations in ice core samples after preconcentrated them by
freeze-drying. INAA is a non-destructive, multi-element technique which is easy to apply
to solid samples.
A significant increase in marine elemental concentrations have been observed
within the time period between 1969 and 1989.
This increase coincided with the
increasing occurrence of the so-called El Niflo Southern Oscillation (ENSO) events in the
Pacific Ocean.
The subsequent analysis showed similar periodicities for the sea-salt
sodium concentrations observed in Antarctica and the sea-level pressure measurements
around Australia which indicates a possible connection between these events.
Similarly, a significant upward trend was observed for crustal aerosol
concentrations after 1980.
The observed ENSO related droughts in the southern
hemisphere are suspected to cause this trend in recent years. At the same time, the annual
average ozone concentrations homogenized between the 600 S and 90' S latitudes shows a
strong negative correlation to the measured aluminum (a crustal aerosol marker)
concentrations between 1979 and 1989.
Recent findings about the importance of
heterogeneous chemical processes and the formation of polar stratospheric clouds (PSC),
on the Antarctic ozone hole gives some incentive for further study, knowing that crustal
aerosols are efficient for cloud nucleation and ice-phase initiation processes. However,
this short time period prevents drawing a strong conclusion from this correlation.
The impact of volcanic emissions on the total atmospheric aerosol budget has long
been recognized and became evident after the recent volcanic eruptions of El Chich6n
(Mexico, 1982) and Mount Pinatubo (Philippines, 1991). In this work antimony and
arsenic were identified as useful marker elements for volcanic emission signals in
Antarctica. Although these elements are already known to be enriched within volcanic
emission plumes, the establishment of the coincidence of their enrichments with the known
120
or suspected volcanic events was essential for their use as marker elements in ice core
research.
The most interesting volcanic episode was observed in 1940, and this event is both
the strongest and longest in duration (1937-44) in the continuous annual sampling period
(1926-1989) of this work. In addition to As and Sb, Cr, Br, Na, and Cl were also
significantly enriched during this period. One strong candidate for this VME's signal is
the 1937-43 eruptions of the Rabaul Volcano in Papua New Guinea. The lack of a high
sulfate signal during those years showed that the volcanic marker elements approach can
be very useful for the identification of historical eruptions from volcanoes with low sulfur
emissions as this one was.
Comparison of the pre-industrial and modem era elemental concentration
measurements indicated some increase for the excess concentrations (i.e. crustal and
marine contributions subtracted) of the elements As, Zn, and Cr in recent years. Since
these elements are known to be enriched in the emissions both from volcanic and
anthropogenic sources, the role of anthropogenic emissions in these trends is not obvious.
However, decreasing antimony concentrations observed after the 1950's is thought to
indicate decreasing impact from volcanic emissions because this element has been well
identified as a volcanic marker element in Antarctica. Therefore, it appears that the
observed increase of As, Zn, and Cr in recent years is partly of anthropogenic origin.
Principal Component Factor Analysis (PCFA), a multivariate statistical analysis
technique, was applied to identify possible correlations among the measured elemental
concentrations.
The results indicated three aerosol source categories for the measured elemental
concentrations in Antarctica. These are crustal, marine, and volcanic sources as identified
by their marker elements. In addition, one factor indicated a possible transition metal
catalyzed release mechanism for gaseous bromine in the Antarctic atmosphere. This may
be the cause of surface level ozone destruction as observed in Greenland.
The accurate determination of the ambient aerosol concentrations is quite
important because of their role in the radiation balance of the Earth/Atmosphere system
To understand the relationship between the elemental concentrations measured in snow
deposits and the ambient atmospheric aerosol concentrations, a simple empirical parameter
(scavenging ratio) was utilized. The results, in spite of the high uncertainties, indicated
generally more efficient scavenging for crustal aerosols followed by marine aerosols and
volatile elements.
Air content measurements of several samples from the NBY-89 ice core by INAA
technique showed good agreement within each of two same-depth layers. Samples from
the adjacent depth levels within an annual accumulation layer showed larger deviation
possibly because of seasonal impacts on the air content.
This new method seems
promising for the air content measurements in very small samples from deep ice cores as
the thin annual accumulation layers in those cores make the availability of large samples
required for conventional measurements almost impossible.
The availability of this
method can ease the dating of deep ice cores, a task necessary for the understanding of the
past environmental history.
4.2.
Suggestions for Future Work
The following considerations during the sampling, preparation, and analysis stages
are thought to be useful to reduce the uncertainties in trace elements measurements:
Cutting a sample from a depth interval that exactly coincides with a specific year,
assuming that the ice core is dated precisely prior to the sampling. This will eliminate
the extra uncertainty involved during the calculation of annual concentrations as
mentioned in section 3.2.
122
* Separating a longitudinal thin slice from each annual sample for use in direct chlorine
measurements (by melting and using an aliquot of it) assures the correct representation
of a full year.
* Obtaining samples for cross-profiling that are large enough to eliminate the need for a
secondary cutting step as mentioned in section 3.1 will reduce the risk of
contamination.
* A special material for sample containers with minimal trace elements content, such as
Teflon MT , will reduce the uncertainties due to the blank correction step as mentioned in
section 3.1.
The following subjects are suggested for future research using polar ice core trace
elements analysis:
* Continuous seasonal measurements of total sodium and chlorine for the last three
centuries to understand the possible ENSO connection in more detail. In addition,
utilizing more sophisticated time-series analysis techniques for examining this data set.
* Analysis of more annual accumulation samples from the depth intervals that contain
well identified large and moderate scale volcanic eruption horizons to further justify
the use of volcanic marker elements approach for historical volcanic eruption
identification.
* Collecting aerosols with longer durations to reduce the uncertainties in ambient
elemental concentrations so that uncertainties in scavenging ratio calculations can be
reduced.
123
Improvement of the developed INAA air-content analysis method by finding additional
methods for keeping the ice samples cooled during the irradiation and gamma-ray
spectroscopy.
124
5.
REFERENCES
Abbatt, J. P. D., and M. J. Molina, 1993, "Status of stratospheric ozone depletion". Annu. Rev. Energy
Environ. v. 18, pp. 1-29.
Alfassi, Z. B.,edt. 1990 "Activation Analysis.", v. 1, 2, CRC Press, Inc.
Artaxo, P., M. L. C. Rabello, W. Maenhaut, and R. Van Grieken, 1992, "Trace elements and individual
particle analysis of atmospheric aerosols from the Antarctic peninsula.", Tellus, v. 44B, pp. 318334.
Barrie, L. A., 1985, "Atmospheric particles: Their physical and chemical characteristics, and deposition
processes relevant to the chemical composition of glaciers", Annals of Glaciology, v. 7, pp. 100108.
Barrie, L. A., 1986, "Arctic air pollution: An overview of current knowledge.", Atmos. Env., v. 20, p.
643.
Barrie, L. A., J. W. Bottenheim, R. C. Schnell, P. J. Crutzen, and R. A. Rasmussen, 1988, "Ozone
destruction and photochemical reactions at polar sunrise in the lower Arctic atmosphere.",
Nature, v. 334, pp. 138-141.
Batifol, F., C. Boutron, and M. de Angelis, 1989, "Changes in copper, zinc, and cadmium concentration
in Antarctic ice during the past 40,000 years.", Nature, v. 337, pp. 544-546.
Beard, K. V., 1992, "Ice initiation in warm-base convective clouds: An assessment of microphysical
mechanisms.", Atmos. Res., v. 28, pp. 125-152.
Blanchard, D. C. and A. H. Woodcock, 1980, "The production, concentration, and vertical distribution of
the sea salt aerosol", Ann. NY Acad. Sci., v. 338, pp. 330-347.
Bloomfield, P., 1976, "FourierAnalysis of Time Series: An introduction.", John Wiley & Sons.
Bluth, G. J. S., C. C. Schnetzler, A. J. Krueger, and L. S. Walter, 1993, Nature, v. 366, p. 327.
Bodhaine, B. A., J. J. Deluisi, J. M. Harris, P. Houmere, and S. Baumen, 1987, "PIXE analysis of South
Pole aerosol", Nucl. Inst. Meth. Phys. Res., v. B22, pp. 241-247.
Bodhaine. B. A., J. J. DeLuisi, J. M. Harris, P. Houmere, and S. Bauman, 1986, "Aerosol measurements
at the South Pole", Tellus, v. 38B, pp. 223-235.
BOhm, J. P., 1992, "A general hydrodynamic theory for mixed-phase microphysics. Part III : Riming and
aggregation.", Atmos. Res., v. 28, pp. 103-123.
Bojkov, R. D., 1986, "Spring-ozone change in Antarctica and the role of the polar vortex", Adv. Space
Res., v. 6, pp. 89-98.
Boutron, C. F. and E. W. Wolff, 1989, "Heavy metal and sulfur emissions to the atmosphere from human
activities in Antarctica.", Atmos. Env., v. 23, pp. 1669-1675.
Boutron, C. F., and C. C. Patterson, 1983, "The occurrence of lead in Antarctic recent snow, firn
deposited over the last two centuries and prehistoric ice.", Geochim. Cosmochim. Acta, v. 47, pp.
1355-1368.
Boutron, C. F., and C. C. Patterson, 1987, "Relative levels of natural and anthropogenic lead in recent
Antarctic snow.", J. Geophy. Res., v. 92, pp. 8454-8464.
Boutron, C., 1980, "Respective influence of global pollution and volcanic eruptions on the past
variationsof the trace metals content of Antarctic snows since 1880's.", J. of Geoph. Res., v. 85,
pp. 7426-7432.
Boutron, C., 1982, "Atmospheric trace metals in the snow layers deposited at the South Pole from 1928 to
1977.", Atmos. Env., v. 16, p. 2451.
Boutron, C., and C. C. Lorius, 1979, "Trace Metals in Antarctic Snows Since 1914.", Nature, v. 277, p.
551.
Buat-M6nard, P., 1990, "Global source strength and long-range atmospheric transport of trace elements
emitted by volcanic activity.", In: The Long-Range Atmospheric Transport of Natural and
ContaminantSubstances, ed. A. H. Knap, Kluwer Academic Publishers, pp. 163-175.
Budd, W.F., 1991, "Antarctica and global change.", Climatic Change, v. 18, pp. 271-299.
125
Burroughs, W. J., 1992, "Weather Cycles Real or Imaginary?", pp. 48-50, 108-117. Cambridge Univ.
Press.
Cadle, R. D., C. S. Kiang, and J. -F. Louis, 1976, "The global scale dispersion of the eruption clouds from
major volcanic eruptions.", J. Geoph. Res., v. 81, pp. 3125-3132.
Carey, J. H., and C. H. Langford, 1975, Canadian Journal of Chem., v. 53, pp. 2436-2440.
Carleton, A. M., 1992, "Synoptic interactions between Antarctica and lower latitudes.", Aust. Met. Mag.,
v.40, pp. 129-147.
Charles, C. D., D. Rind, J. Jouzel, R. D. Koster, and R. G.Fairbanks, 1994, "Glacial-interglacial changes
in moisture sources for Greenland: Influences on the ice core record of climate.", Science, v. 263,
pp. 508-511.
J. E. Lovelock, M. O. Andreae, and S. G. Warren, 1987, "Oceanic phytoplankton,
Charlson, R. J.,
atmospheric sulphur, cloud albedo and climate.", Nature, v. 326, pp. 655-661.
Comrey, A. L., 1973, "A First Course in FactorAnalysis.", Academic Press. New York.
Crowley, T. J., T. A. Criste, and N. R. Smith, 1993, "Reassessment of Crete (Greenland) ice core
acidity/volcanism link to climate change.", Geoph. Res. Lett., v. 20, pp. 209-212.
Cunningham, W. C., W. H. Zoller, 1981, "The chemical composition of remote area aerosols", J. of
Aerosol Science, v. 12, pp. 367-384.
d'Almeida, G. A., and L. Schtitz, 1983, "Number, mass, and volume distributions of mineral aerosol and
soils of the Sahara.", J. Clim. Appl. Meteor., v. 25, pp. 233-243.
Dai, J., E.Mosley-Thompson, and L. G. Thompson, 1991, "Ice core evidence for an explosive tropical
volcanic eruption 6 years preceding Tambora.", J. Geoph. Res., v. 96, pp. 17361-17366.
Danielsen, E. F., 1968, "Stratospheric-tropospheric exchange based on radioactivity, ozone, and potential
vorticity", J. of Atmospheric Science, v. 25, pp. 502-518.
Dansgaard, W., 1954, "Oxygen-18 abundance in fresh water.", Nature, v. 174, p. 2 3 4 .
Davidson, C. I., 1989, "Mechanisms of wet and dry deposition of atmospheric contaminants to snow
surfaces.", In: The EnvironmentalRecord in Glaciers and Ice Sheets. eds. H. Oeschger and C.C.
Langway, Jr., John Wiley & Sons.
Davidson, C. I., C. Liyang, T. C. Grim, M. A. Nasta, and M. P. Qamoos, 1981, "Wet and Dry Deposition
of Trace Elements Onto the Greenland Ice Sheet.", Atmospheric Environment, v. 15, pp. 14291437.
Davidson, C. I., R. E. Honrath, J. B. Kadane, R. S. Tsay, P. A. Mayewski. W. B. Lyons, and N. Z.
Heidam, 1987, "The scavenging of atmospheric sulfate by Arctic snow.", Atmos. Env., v. 21, pp.
871-882.
De Angelis, M., N. I. Barkov, and V. N. Petrov, 1987 "Aerosol concentrations over the last climatic cycle
(160 kyr) from an Antarctic ice core.", Nature, v. 325, pp. 318-321.
Delmas, R. J., and M. Legrand, 1989, "Long-term changes in the concentrations of major chemical
compounds (soluble and insoluble) along deep ice cores.", In: The Environmental Record in
Glaciers and Ice Sheets, eds. H. Oeschger and C. C. Langway, Jr., John Wiley & Sons, pp. 319341.
Delmas, R. J., S. Kirchner, J. M. Palais, and J.-R. Petit, 1992, "1000 years of explosive volcanism
recorded at the South Pole.", Tellus, v. 44B, pp. 335-350.
Deshler, T., D. J. Hofmann, J. V. Hereford, and C. B. Sutter, 1990, "Vertical profiles of ozone and aerosol
at McMurdo Station, Antarctica, in the spring of 1989", Antarctic Journal, 1990 Review.
Dick, A. L., 1990, "A simple model for air/snow fractionation of aerosol components over the Antarctic
peninsula.", J. Atmos. Chem., v. 11, pp. 179-196.
Dick, A. L., 1991, "Concentrations and sources of metals in the Antarctic Peninsula aerosol", Geochimica
et Cosmochimica Acta, v. 55, pp. 1827-1836.
Duce, R. A., J. W. Winchester, and T. W. Van Nahl, 1965, "Iodine, bromine, and chlorine in Hawaian
marine atmosphere", J. Geophysical Research, v. 70, pp. 1775-1799.
Dunbar, N. W. and P. R. Kyle, 1990, "Volatile contents of melt inclusions in anorthoclase phenocrysts
from Mount Erebus: Implications for magmatic crystallization.", Antarctic Journal, 1990
Review, pp.7-9.
126
Ellsaesser, H. W., 1983, "Stratospheric water vapor", J. of Geophysical Research, v. 88, pp. 3897-3906
Fahnestock, M., R. Bindschadler, R. Kwok, and K. Jezek, 1993, "Greenland ice sheet surface properties
and ice dynamics from ERS-1 SAR imagery",Science, v. 262, pp. 1530-1534.
Fairall, C. W., K. L. Davidson, and G. E. Schacher, 1983, "An analysis of the surface production of seasalt aerosols", Tellus, v. 35B, pp. 31-39.
Fan, S-M., and D. J. Jacob, 1992, "Surface ozone depletion in Arctic spring sustained by bromine
reactions on aerosols.", Nature, v. 359, pp. 522-524.
Farman, J. C., B. G. Gardiner, and J. D. Shanklin, 1985, "Large losses of total ozone in Antarctica reveal
seasonal CIOx/NOx interaction", Nature, v. 315, pp. 207-210.
Fletcher, N. H., 1958, "Size effect in heterogeneous nucleation.", J. of Chem. Phys., v. 29, pp. 572-576.
Flossmann, A. I., 1991, "The scavenging of two different types of marine aerosol particles calculated
using a two-dimensional detailed cloud model.", Tellus, v. 43B, pp. 301-321.
Fogg, G. E., 1992, "A History ofAntarctic Science" Cambridge University Press.
Frank, G., J. Tschiersch, and H. Behrens, 1990, "Wet deposition of tracer-marked aerosol.", J. Aerosol
Sci., v. 21, suppl. 1, pp. S213-S216.
Garcia, R., 1994, "Causes of ozone depletion.", Physics World, April, pp. 49-55.
Gaudichet, A., M. De Angelis, S. Joussaume, J. R. Petit, Y. S. Korotkevitch, and V. N. Petrov, 1992,
"Comments on the origin of dust in East Antarctica for present and ice age conditions", J. of
Atmospheric Chemistry, v. 14, pp. 129-142.
Ghan, S. J., K. E. Taylor, and J. E. Penner, 1990, "Model Test of CCN-Cloud Albedo climate Forcing.",
Geophysical Research Letters, v. 17, pp. 607-610.
Goldberg, E. D., 1963, "The oceans as a chemical system.", In: The Sea. v. 2, edt. M. N. Hill, pp. 23,
Wiley-Interscience.
Goldstein, R. M., H. Engelhardt, B. Kamb, and R. M. Frolich, 1993, "Satellite radar interferometry for
monitoring ice sheet motion: Application to an Antarctic ice stream", Science, v. 262, pp. 15251530.
Golub, G. H., and C. F. Van Loan, 1989, "Matrix Computations.", The Johns Hopkins Unv. Press, pp.
331-340.
Gomes, L., and D. A. Gillette, 1992, "Chemical and mineral composition by size of dust deposited during
dust storms in SW Tadzhikistan", In: Precipitation Scavenging and Atmosphere-Surface
Exchange, v.2, pp. 921-932.
Gordon, G. E., W. H. Zoller, E. S. Gladney, and A. G. Jones, 1971, "In: Proceedings of the ANS Topical
Meeting on Nuclear Methods in EnvironmentalResearch.", Univ. of Mo., Columbia, p. 30.
Girlach, U., and C. F. Boutron, 1990, "Preconcentration of lead, cadmium, copper and zinc in water at
the pg g-1 level by non-boiling evaporation.", Analytica Chimica Acta, v. 236, pp. 391-398.
Gorlach, U., and C. F. Boutron, 1992, "Variations in heavy metals concentrations in Antarctic snows from
1940 to 1980.", J. Atmos. Chem., v. 14, pp. 205-222.
Grant, W. B., J. Fishman, E. V. Browell, V. G. Brackett, D. Nganga, et al., 1992, "Observations of
reduced ozone concentrations in the tropical stratosphere after the eruption of Mt. Pinatubo",
Geophys. Res. Lett., v. 19, pp. 1109-1112.
Grassl, H., 1988, "What Are the Radiative and Climatic Consequences of the Changing Concentration of
Atmospheric Aerosol Particles?.", In: The ChangingAtmosphere. eds. F. S. Rowland and I. S. A.
Isaksen, pp. 187-199.
Guerzoni, S, R. Lenaz, G. Quarantotto, and M. Taviani, 1992, "Geochemistry of airborne particles from
the lower troposphere of Terra Nova Bay, Antarctica", Tellus, v. 44B, pp. 304-310.
Hamill, P., and 0. B. Toon, 1991, "Polar stratospheric clouds and the ozone hole", Physics Today, pp. 3442.
Hammer, C. U., 1983, "Initial direct current in the build-up of space charges and the acidity of ice cores.",
J. Physical Chem., v. 87, p. 4099-4103.
Hammer, C. U., 1985, "The influence on atmospheric composition of volcanic eruptions as derived from
ice-core analysis.", Annals of Glaciology, v. 7, pp. 125-129.
127
Hammer, C. U., 1989, "Dating by physical and chemical seasonal variations and reference horizons.", In:
The Environmental Record in Glaciersand Ice Sheets, eds. H. Oeschger and C. C. Langway, Jr.,
John Wiley & Sons, p. 99-121.
Hammer, C. U., H. B. Clausen, and C. C. Langway, Jr., 1985, "The Byrd Ice Core: continuous acidity
measurements and solid electrical conductivity measurements.", Annals of Glaciology, v. 7, p.
214.
Hammer, C. U., H. B. Clausen, and H. Tauber, 1986, "Ice core dating of the Pleistocene/Halocene
boundary applied to a calibration of the 14C time scale.", Radiocarbon, v. 28, pp. 284-291.
Handler, P., 1989, "The effect of volcanic aerosols on global climate.", J. Volcanol. Geotherm. Process., v.
37, pp. 233-249.
Hanson, D., and K. Mauersberger, 1988a, "Laboratory studies of the nitric acid trihydrate: Implications
for the south polar stratosphere", Geophy. Res. Lett., v. 15, pp. 855-858.
Hanson, D., and K. Mauersberger, 1988b, "Vapor pressures of HNO3/H 20 solutions at low temperatures",
J. Phys. Chem., v. 92, pp. 6167-6170.
Harman, H. H., 1976, "Modern FactorAnalysis", Unv. of Chicago Press, Chicago.
Harrison, S. H., 1977, "Trace Elements in Water: A Development and Application of Sampling and
Sample Handling Procedures.",Ph. D. Thesis, University of Maryland.
Harriss, R. C., R. J. Charlson, R. J. Delmas, U. Feister, C. C. Langway, Jr., J. E.Lovelock, G. I. Pearman,
R. G. Prinn, W. Seiler, B. R. Stauffer, and R. F. Weiss, 1988, "How has the atmosphere already
changed?", In: The ChangingAtmosphere, eds. F. S. Rowland and I. S. A. Isaksen, John Wiley &
Sons, pp. 201-216.
Henry, R. C., 1991, "MultivariateReceptor Models", In Receptor modeling for air quality management,
ed. P. K. Hopke, pp. 117-147.
Henry, R. C., C. W. Lewis, P. K. Hopke, and H. J. Williamson, 1984, "Review of receptor model
fundamentals", Atmospheric Env., v. 18, pp. 1507-1515.
Hermann, D., and I. Olmez, 1990, "Source attribution studies in Eastern Massachusetts", Presentation at
the 83rd Annual Meeting of Air & Waste Management Association, June 24-29, Pittsburgh, PA.
Herron, M. M., 1982, "Glaciochemical dating techniques." In: Nuclear and Chemical Dating Techniques,
Interpretingthe Environmental Record, ed. L. A. Currie. ACS Symposium Series, 176, pp. 303318.
Herron, S. L., 1982b, "PhysicalPropertiesof the Deep Ice Core from Camp Century, Greenland"', Ph. D.
Thesis, State University of New York at Buffalo.
Hobbs, P. V., 1993, "Aerosol-cloud interactions.", In: Aerosol-Cloud-Climate Interactions, ed. P. V.
Hobbs, Academic Press, Inc.
Hofmann. D. J., and S. Solomon, 1989, "Ozone destruction through heterogeneous chemistry following
the eruption of El Chichon", J. Geophys. Res., v. 94, pp. 5029-5041.
Hofmann, D. J., J. W. Harder, S. R. Rolf, and J. M. Rosen, 1987, "Balloonborne observations of the
temporal development and vertical structure of the Antarctic ozone hole in 1986", Nature, v. 326,
pp. 59-62.
Hofmann, D. J., S. J. Oltmans, J. M. Harris, S. Solomon, T. Deshler, and B. J. Johnson, 1992,
"Observation and possible causes of new ozone depletion in Antarctica in 1991", Nature, v. 359,
pp. 283-287.
Hogan, A. W., W. G. Egan, J. A. Samson, S. C. Barnard, D. M. Riley, and B. B. Murphy, 1990,
"Seasonal variation of some constituents of Antarctic tropospheric air", Geophy. Res. Lett., v. 17,
pp. 2365-2368.
Hogan, A., K. Kebschull, R. Townsend, B. Murphey, J. Samson, and S. Barnard, 1984, "Particle
concentrations at the South Pole, on meteorological and climatological time scales; is the
difference important?", Geophy. Res. Lett., v. 1, pp. 850-853.
Horibe, Y., K. Shigehara, and C. C. Langway, Jr., 1985, "Chemical and isotopic composition of air
inclusions in a Greenland ice core", Earth and Planetary Science Letters, v. 73, pp. 207-210.
Huang, X, I. Olmez, and N. K. Aras, 1994, "Emissions of trace elements from motor vehicles: Potential
marker elements and source composition profile.", Atmos. Environ., v. 28, pp. 1385-1391.
128
Ibrahim, M., L. A. Barrie, and F. Fanaki, 1983, "An experimental and theoretical investigation of the dry
deposition of particles to snow, pine trees, and artificial collectors.", Atmospheric Environment,
v. 17, pp. 781-788.
Idso, S. B., 1992, "The DMS-cloud albedo feedback effect: Greatly underestimated?", Climatic Change, v.
21, pp. 429-433.
Ivey, J.P., and D.M. Davies, 1987, "Ion Chromatographic Determination of Selected Ions in Antarctic
Ice.", Analytica Chimica Acta, v. 194, p. 281.
Jaenicke, R., 1993, "Tropospheric aerosols", In: Aerosol-Cloud-Climate Interactions, ed. P. V. Hobbs,
Academic Press pp. 1-31.
Johnsen, S. J., 1977, "Stable isotope homogenization of polar firn and ice." In: Isotopes and Impurities in
Snow and Ice, Proc. IU66 Symposium, Grenoble, 1975. IAHS-AISH Publication 118, p. 210219.
Jouzel, J., and L. Merlivat, 1984, "Deuterium and oxygen 18 in precipitation: modeling of the isotopic
effect during snow formation.", J. Geophys. Res., v. 89, pp. 11749-11757.
Junge, C. and R. Jaenicke, 1971, J. Aerosol Sci. v. 2, pp. 305-314.
Junge, C. E., 1963, "Air Chemistry and Radioactivity", International Geophysical Series, v. 4, Academic
Press, NY.
Junge, C. E., 1977, "Processes responsible for the trace content in precipitation", In: Isotopes and
Impurities in Snow and Ice, IAHS, Publication 118, pp. 63-77.
Kaiser, H. F., 1958, "The varimax criterion for analytic rotation in factor analysis.", Psychometrica, v. 23,
pp. 187-200.
Keene, W. C., A. A. P. Pszenny, J. N. Galloway, and M. E. Hawley, 1986, "Seasalt corrections and
interpretation of constituent ratios in marine precipitation", J. of Geophy. Res., v. 91, pp. 66476658.
Keskin, S.S., X. Huang, I. Olmez, and C.C. Langway, Jr., "Trace Elements in a Dated Ice Core From
Antarctica", (Abstract), American Nuclear Society, National Meeting. June 7-12. 1992, Boston.
MA.
Khalil, M. A. K. and F. P. Moraes, 1995, "Linear Least Squares method for time series analysis with an
application to a methane time series.", J. Air&Waste Manag. Assoc.. v. 45, pp. 62-63.
Kley, D., 1983, "The budget of tropospheric nitrate in remote oceanic regions." Paper presented at the 5th
CACGP International Conference, Oxford, Aug, 28- Sep. 4.
Knoll, G. F., 1989, "RadiationDetection and Measurement", John Wiley and Sons.
Kotra, J. P., D. L. Finnegan, W. H. Zoller, M. A. Hart, and J. L. Moyers, 1983, "El Chich6n: Composition
of plume gases and particles.", Science, v. 222, pp. 1018-1021.
Kritz, M. A. and J. Rancher, 1980, "Circulation of Na, Cl, and Br in the tropical marine atmosphere", J.
of Geophy. Res., v. 85, pp. 1633-1639.
Kumai, M., 1976, "Identification of nuclei and concentrations of chemical species in snow crystals
sampled at the South Pole.", J. Atmos. Sci., v. 33, pp. 833-841.
Kyle, P. R., K. Meeker, and D. Finnegan, 1990, "Emission rates of sulfur dioxide, trace gases and metals
from Mount Erebus, Antarctica.", Geoph. Res. Lett., v. 17, pp. 2125-2128.
Lal, M., and R. K. Kapoor, 1992, "Submicron aerosols over Indian Ocean: some meteorological
characteristics", Atmospheric Research, v. 27, pp. 291-303.
Langway, C. C., Jr., 1958, ""Bubble pressures in Greenland glacier ice, Symposium of Chamonix, Physics
of the movement of ice (Proceedings of the Chamonix Symposium, 1958), IAHS-AISH Pub. no.
47, pp. 336-349.
Langway, C. C. Jr., 1970, "Stratigraphic analysis of a deep ice core from Greenland.", Geological Society
of America, Special Paper 125.
Langway, C. C., Jr., 1992, "A shallow ice core drilling project at Byrd Station, Antarctica.", Ant. Jour.
U.S., 1991 Review v. 26, p.60-61.
Langway, C. C., Jr., G. A. Klouda, M. M. Herron, and J. H. Cragin, 1977, "Seasonalvariations of
chemical constituents in annual layers of Greenland deep ice deposits.", In: Isotopes and
Impurities in Snow and Ice, Proceedings of IUGG Symposium, Grenoble, 1975. IAHS-AISH
Publ. 118: 302-306.
129
Langway, C. C., Jr., H. B. Clausen, and C. U. Hammer, 1995b, "The stable isotope, acidity, and P-activity
levels in a 1360-year-old ice core from Byrd Station, Antarctica.", Manuscript in preparation.
Langway, C. C., Jr., H. Shoji, A. Mitani, and H. B. Clausen, 1993, "Transformation process observations
of polar firn to ice.", Annals of Glaciology, v. 18, p. 199-202.
Langway, C. C., Jr., K. Osada, H. B. Clausen, C. U. Hammer, and H. Shoji, 1995a, "A ten century
comparison of prominent bi-polar volcanic events in ice cores.", Manuscript in preparation.
Langway, C. C., Jr., K. Osada, H. B. Clausen, C. U. Hammer, H. Shoji, and A. Mitani, 1994, "New
chemical stratigraphy over the last millennium for Byrd Station, Antarctica.", Tellus, v. 46B, pp.
40-51.
Langway, C. C., Jr., M. M. Herron, and J. H. Cragin, 1974, "Chemical profile of the Ross Ice Sheet at
Little America V, Antarctica.", J. Glaciology, v.13, pp. 431-435.
Legrand, M. R. and R. J. Delmas, 1988, "Formation of HC1 in the Antarctic atmosphere", J. of
Geophysical Research, v. 93, pp. 7153-7168.
Legrand, M. R., C. Lorius, N. I. Barkov, and V. N. Petrov, 1988b, "Vostok (Antarctica) ice core:
Atmospheric chemistry changes over the last climatic cycle (160,000 years).", Atmos. Env., v.
22, pp. 317-331.
Legrand, M., and R. J. Delmas, 1984, "The ionic balance of Antarctic snow: a 10 yr detailed record.",
Atmos. Envir., v. 18, pp. 1867-1874.
Lindqvist, 0., 1985, "Atmospheric mercury-a review.", Tellus, v. 37B, pp. 136-159.
Loureiro, A. L. M., M. B. A. Vasconcellos, and E. B. Pereira, 1992, "Trace element determination in
aerosols from the Antarctic Peninsula by neutron activation analysis", J. Radioanaly. and Nuc.
Chem., v. 159, pp. 21-28.
Lowenthal, D. H., and K. A. Rahn, 1985, "Regional sources of pollution aerosols at Barrow, Alaska,
during winter 1979-80 as deduced from elemental tracers.", Atmos. Environ., v. 19, p. 2011.
Lowenthal, D. H., and K. A. Rahn, 1987, "Application of the factor-analysis receptor model to simulated
urban- and regional-scale data sets", Atmospheric Env., v. 21, pp. 2005-2013.
Maenhaut, W., W. H. Zoller, R. A. Duce, and G. L. Hoffman, 1979, "Concentration and size distribution
of particulate trace elements in the South Polar atmosphere", J. of Geophy. Res., v. 84, pp. 24212431.
Malinowski, E. R. and D. G. Howery, 1980, "FactorAnalysis in Chemistry.", John Wiley, New York.
Mardia, K.V., J. T. Kent, and J. M. Bibby, 1992, "Multivariate Analysis", Academic Press, Inc., San
Diego, California.
Martinerie, P., D. Raynaud, D. M. Etheridge, J.-M. Barnola, and D. Mazaudier, 1992, "Physical and
climatic parameters which influence the air content in polar ice", Earth and Planetary Science
Letters, v. 112, pp. 1-13.
McConnell, J. C., G. S. Henderson, L. Barrie, J. Bottenheim, H. Niki, C. H. Langford, and E. M. J.
Templeton, 1992, "Photochemical bromine production implicated in Arctic boundary-layer ozone
depletion", Nature, v. 355, pp. 150-152.
McCormick, and M. P. and C. R. Trepte, 1986, "SAM II measurements of Antarctic PSCs and aerosols",
Geophy. Res. Lett., v. 13, pp. 1276-1279.
McElroy, M. B., R. J. Salawitch, S. C. Wofsy, and J. A. Logan, 1986, "Reductions of Antarctic ozone due
to synergistic interactions of chlorine and bromine", Nature, v. 321, pp. 759-762.
Meanhaut, W., W. H. Zoller, R. A. Duce, and G. L. Hoffman, 1979, "Concentration and size distribution
of Particulate Trace Elements in the South Pole Atmosphere.", J. Geophys. Res., v. 84, p. 2421.
Mdsz~ros, A. and K. Vissy, 1974, J. Aerosol Sci. v. 5, pp. 101-109.
Michelangeli, D. V., M. Allen, and Y. L. Yung, 1989, "El Chichon volcanic aerosols: Impact of radiative,
thermal, and chemical perturbations.", J. Geophy. Res., v. 94, pp. 18429-18443.
Miller, N. L., and P. K. Wang, 1991, "A theoretical determination of the collection rates of aerosol
particles by falling ice crystal plates and columns.", Atmos. Env., v. 25A, pp. 2593-2606.
Molina, L. T., and M. J. Molina, 1987, "Production of C1202 from the self-reaction of the CIO radical" J.
of Physical Chemistry, v. 91, pp. 433-436.
130
Molina, M. J., 1991, "Heterogeneous chemistry on polar stratospheric clouds", Atmos. Env., v. 25A, pp.
2535-2537.
Molina, M. J., and F. S. Rowland, 1974, "Stratospheric sink for chlorofluoromethanes: Chlorine atom
catalyzed destruction of ozone", Nature, v. 249, pp. 810-812.
T.-L. Tso, L. T. Molina, and F.C.-Y. Wang, 1987, "Antarctic stratospheric chemistry of
Molina, M. J.,
chlorine nitrate, hydrogen chloride and ice: Release of active chlorine", Science, v. 238, pp.
1253-1257.
Moore, J. C., 1991, H. Narita, and N. Maeno, 1991, "A continuous 770-year record of volcanic activity
from East Antarctica.", J. Geoph. Res., v. 96, pp. 17353-17359.
Moraes, F. P. and M. A. K. Khalil, 1993, "LLSSA: Acomputer programfor spectral analysis of unevenly
spaced data.", Technical Report, Oregon Graduate Institute.
Murphey, B. B., T. Hare, A. W. Hogan, K. Lieser, J. Toman, and T. Woodgates, 1991, "Vernal
atmospheric mixing in the Antarctic", J. of Applied Meteorology, v. 30, pp. 494-507.
Neftel, A., P. Jacob, and D. Klockow, 1984, "Measurements of hydrogen peroxide in polar ice samples.",
Nature, v. 311, pp. 43-45.
Newhall, C. G.and S. Self, 1982, "The volcanic explosivity index (VEI): An estimate of explosive
magnitude for historical volcanism.", J. of Geoph. Res., v.87, pp. 1231-1238.
Noll, K. E., and K. Y. P. Fang, 1989, "Development of a dry deposition model for atmospheric coarse
particles.", Atmos. Env., v. 23, pp. 585-594.
Okamoto, S., M. Hayashi, M. Nakajima, Y. Kainuma, and K. Shiozawa, 1990, "A factor analysis-multiple
regression model for source apportionment of suspended particulate matter.", Atmos. Env., v.
24A, pp. 2089-2097.
Olmez, I., 1989, "Instrumental Neutron Activation Analysis of atmospheric particulate matter.", In:
Methods ofAir Sampling and Analysis, ed. J. P. Lodge, Jr., Lewis Publishers, Inc.
Olmez, I., A.E. Sheffield, G. E.Gordon, J. E.Houck, L. C. Pritchett, J. A. Cooper, T. G. Dzubay, and R.
L. Bennett, 1988, "Compositions of particles from selected sources in Philadelphia for receptor
modelling applications.", J. Air Pollut. Cont. Assoc., v. 33, p. 1392.
Olmez, I., and G. E.Gordon, 1985, "Rare earths: Atmospheric signatures for oil-fired power plants and
refineries.", Science, v. 229, p. 966.
Olmez, I., D. L Finnegan, and W. H. Zoller, 1986, "Iridium emissions from Kilauea Volcano.", J.
Geophys. Res., v. 91, pp. 653-663.
Olmez, I., E.L. Fireman, and C.C. Langway, Jr., 1993, "Trace elements in basal ice at Dye-3.", Atmos.
Env., v. 27A, pp. 2921-2926.
Olmez, I., J. W. Beal, and J. F. Villaume, 1994, "A new approach to understanding multiple-source
groundwater contamination: Factor Analysis and Chemical Mass Balances.", Wat. Res., v. 28,
pp. 1095-1101.
Orheim, 0., 1972, "Volcanic activity on Deception Island, South Shetland Islands.", In: Anarctic Geology
and Geophysics, ed. R. J. Adie, pp. 117-120. Universitetsforlaget, Oslo, 1972.
Ott, W. R., 1990, "A Physical explanation of the lognormality of pollutant concentrations.", J. Air Waste
Manag., v.40, pp. 1378-1383.
Palais, J. M. and B. W. Mosher, 1989, "Elemental tracers of volcanic emissions in Antarctic aerosol and
snow samples.", Antarctic Journal, 1989 Review, pp. 217-218.
Palais, J. M. and M. Legrand, 1985, "Soluble impurities in the Byrd Station ice core, Antarctica: Their
origin and sources.", J.Geophy. Res., v. 90, pp. 1143.
Palais, J. M., S. Kirchner, and R. Delmas, 1989, "Identification and correlation of volcanic eruption
horizons in a 1000-year ice-core record from the South Pole.", Antarctic Journal, 1989 Review,
pp. 101-104.
Parungo, F., B. Bodhaine, and J. Bortniak, 1981, "Seasonal variation in Antarctic aerosol", J. of Aerosol
Science, v. 12, pp. 491-504.
Peel, D. A., and E.W. Wolff, 1982, "Recent variations in heavy metal concentrations in firn and air from
the Antarctic peninsula.", Ann. Glacio., v. 3, pp. 255-259.
131
Peel, D.A., 1989, "Trace metals and organic compounds in ice cores in the environmental record in
glaciers and ice sheets.", In: The Environmental Record in Glaciers and Ice Sheets, eds. H.
Oeschger and C. C. Langway, Jr., John Wiley and Sons, p.207.
Petit, J. R., M. Briat, and A. Royer, 1981, "Ice age aerosol content from East Antarctic ice core samples
and past wind strength.", Nature, v. 293, pp. 391.
Phelan Kotra, J., D. L. Finnegan, W. H. Zoller, M. A. Hart, and J. L. Moyers, 1983, "El Chich6n:
Composition of plume gases and particles.", Science. v. 222, pp. 1018-1021.
Phelan, J. M., D. L. Finnegan, D. S. Ballantine, W. H. Zoller, M. A. Hart, and J. L. Moyers, 1982,
"Airborne aerosol measurements in the quiescent plume of Mount St. Helens: September, 1980.",
Geoph. Res. Lett., v. 9, pp. 1093-1096.
Powers, C. F., and D. L. Rambo, 1981, "The occurrence of acid precipitation on the West Coast of the
United States.", Environ. Monitoring Assess., v. 1, pp. 93-105.
Prather, M. J., 1992, "More rapid polar ozone depletion through the reaction of HOCI with HCI on polar
stratospheric clouds", Nature, v. 355, pp. 534-537.
Preining, 0., 1991, "Aerosol and climate-An overview.", Atmos. Env., v. 25A, pp. 2443-2444.
Pyle, J. A., C. Bruhl, R. J. Cicerone, H. Grassl, B. Jahne, M. A. K. Khalil, I. Levin, Y. Makide, H.
Oeschger, 1988, "Group Report: Trace Substances, Radiation Balance, and the Climate of the
Earth.", In: The ChangingAtmosphere. eds. F. S. Rowland and I. S. A. Isaksen, pp. 259-269.
Qin, Y., 1992, "Numerical simulation of pollutants removal by precipitation.", J. Atmos. Chem., v. 14,
pp. 143-151.
Raemdonck, H. W., W. Maenhaut, M. O. Andreae, 1986, "Chemistry of marine aerosol over the tropical
and equatorial Pacific, J. Geophys. Res., v. 91, pp. 8623-8636.
Rahn, K. A., and R. J. McCaffrey, 1979, "Compositional Difference Between Arctic Aerosol and Snow.",
Nature, v. 280, pp. 479-480.
Ramanathan, V., 1988, "The radiative and climatic consequences of the changing atmospheric
composition of trace gases.", In: The Changing Atmosphere, eds. F. S. Rowland and I. S. A.
Isaksen, John Wiley & Sons, pp. 159-199.
Rampino, M. R., and S. Self, 1982, "Historic eruptions of Tambora (1815), Krakatau (1883), and Agung
(1963): Their stratospheric aerosols and climatic impact.", Ouart. Res.. v. 18. pp. 127-143.
Raynaud, D., and B. Lebel, 1979, "Total gas content and surface elevation of polar ice sheets", Nature, v.
281, pp. 289-291.
Rowland, F. S., 1991, "Stratospheric ozone depletion", Annu. Rev. Phys. Chem.. v. 42, pp. 731-768.
Rummel, R. J., 1970, "Applied FactorAnalysis", Northwestern Unv. Press, Evanston, Illinois.
Russell-Head, D. S., and W. F. Budd, 1979, "Ice-sheet flow properties derived from bore-hole shear
measurements combined with ice-core studies", J. of Glaciology, v. 24, pp. 117-130.
Saigne, C., S. Kirchner, and M. Legrand, 1987, "Ion-Chromatographic Measurements of Ammonium,
Fluoride, Acetate, Formate, and Methanesulphonate Ions at Very Low Levels in Antarctic Ice.",
Analytica Chimica Acta, v. 203, p. 11.
Schneider, S. H., 1994, "Detecting climatic change signals: Are there any 'fingerprints'?", Science, v.
263, pp. 341-347.
Schroeder, J. H., 1985, "Eolian dust in the coastal desert of the Sudan: Aggregates cemented by
evaporates.", J. of African Earth Science, v. 3, pp. 371-380.
Schulist, S. 0., and G. N. Freeman, 1992, "A hybrid bin-moment model for aerosol nucleation.",
Particulate Sci. and Tech., v. 10, pp. 65-72.
Seinfeld, J. H., 1986, "Atmospheric Chemistry and Physics of Air Pollution.", John Wiley & Sons, Inc.
Shaw, G. E., 1979, "Considerations on the origin and properties of the Antarctic aerosol", Rew. of
Geophysics and Space Physics, v. 17, pp. 1983-1998.
Shaw, G. E., 1980, "Optical, Chemical, and Physical Properties of Aerosols Over the Antarctic Ice
Sheet.", Atmos. Env., v. 14, pp. 911-921.
Shaw, G. E., 1989, "Aerosol transport from sources to ice sheets.", In: The Environmental Record in
Glaciersand Ice Sheets, eds. H. Oeschger and C.C. Langway, Jr., John Wiley & Sons.
132
Shoji, H., and C. C. Langway, Jr., 1989, "Physical property reference horizons", In: The Environmental
Record in Glaciers and Ice Sheets, eds. H. Oeschger and C. C. Langway, Jr.. John Wiley & Sons,
p. 99-121.
Simkin, T., 1994, "Distant effect of volcanism-How big and how often?", Science. v. 264. pp. 913-914.
Simkin, T., L. Siebert, L. McClelland, D. Bridge, C. Newhall, and J. H. Latter, 1981, "Volcanoes of the
World.", Hutchinson Ross Pub. Co.
Simmonds, I., 1990, "Review: Improvements in General Circulation Model performance in simulating
Antarctic climate.", Antarctic Science, v. 2, pp. 287-300.
Solomon, S., 1990, "Progress towards a quantitative understanding of Antarctic ozone depletion ",
Nature, v. 347, pp. 347-354.
Solomon, S., R. R. Garcia, F. S. Rowland, and D. J.Wuebbles, 1986, "On the depletion of Antarctic
ozone", Nature, v. 321, pp. 755-758.
Stauffer, B. R., 1989, "Dating of ice by radioactive isotopes.", In: The Environmental Record in Glaciers
and Ice Sheets, eds. H. Oeschger and C. C. Langway, Jr., John Wiley & Sons, p. 123-139.
Suttie, E. D., and E.W. Wolff, 1992, "Seasonal input of heavy metals to Antarctic snow.", Tellus, v. 44B,
pp. 351-357.
Tanizaki, Y., 1990, "Neutron activation analysis of water samples.", In: Activation Analysis, v. 2,Ed. Z.
B. Alfassi, CRC Press, Inc., pp. 377-405.
Taylor, S.R., 1972, "Abundance of chemical elements in the continental crust: A new table",
Geochimica et Cosmochimica Acta, v. 28, p. 1273.
Thompson, L. G., 1977, "Variations in microparticle concentration, size distribution, elemental
composition found in Camp Century, Greenland, and Byrd Station, Antarctica, deep cores." In:
Isotopes and Impurities in Snow and Ice, Proceedings of IUGG Symposium, Grenoble, 1975.
IAHS-AISH Publ. 118: 351-364.
Tlisov, M. I., V. N. Filatkin, and I. I. Pilip, 1992, "Heat and mass transfer of drops and growth and
melting of freely floating hailstones.", Atmos. Res., v. 28, pp. 21-39.
Tolbert, M. A., M. J. Rossi, and D. M. Golden, 1988, "Antarctic ozone depletion chemistry: reactions of
N20 5 with H20 and HCI on ice surfaces", Science, v. 240, pp. 1018-1021.
Tolbert, M. A., M. J.Rossi, R. Malhotra, and D. M. Golden, 1987, "Reaction of chlorine nitrate with
hydrogen chloride and water at Antarctic stratospheric temperatures", Science, v. 238, pp. 12581260.
Toon, O. B., R. P. Turco, J. J.Jordan, J. Goodman, and G. Ferry, 1989, "'Physical processes in polar
stratospheric ice clouds", J. of Geophysical Research, v. 94, pp. 11359-11380.
Tuncel, G., and W. H. Zoller, 1995, "Temporal variations and sources of elements in the South Pole
atmosphere: 2. Enriched elements and halogens.", Manuscript in preparation.
Tuncel, G., N. K. Aras, and W. H. Zoller, 1989, "Temporal variations and sources of elements in the
South Pole atmosphere: 1. Nonenriched and moderately enriched elements", J. of Geophysical
Research, v. 94, no. D10, pp. 13025-13038.
Twomey, S., M. Piepgrass, and T. L. Wolfe, 1984, "An assessment of the impact of pollution on global
cloud albedo.", Tellus, v. 36B, pp. 356-366.
Ueda, H. T., and D. E. Garfield, 1969, "Core drilling thorough the Antarctic Ice Sheet." CRREL
Technical Report 231, Hanover, New Hampshire, U.S. Army Cold Regions Research and
Engineering Laboratory, 20 p.
Van Loon, H., 1972, "Wind in the Southern Hemisphere", In: Meteorology of the Southern Hemisphere,
Ed. C. Newton, Meteor. Monogr., No. 35, American Meteor. Soc., pp. 549-552.
Wagenbach, D., U. Girlach, K. Moser, and K. O. Miinnich, 1988, "Coastal Antarctic aerosol: the
seasonal pattern of its chemical composition and radionuclide content.", Tellus, v. 40B, pp. 426436.
Wallace, J. M. and S. Vogel, 1994, "El Nifio and Climate Prediction", Reports to The Nation, Spring
1994, No. 3.
Wallace, P. J., and T. M. Gerlach, 1994, "Magmatic vapor source for sulfur dioxide released during
volcanic eruptions: Evidence from Mount Pinatubo.", Science, v. 265, pp. 497-499.
133
Walton, D. W. H., 1987, "Antarctic Science" Cambridge University Press.
Williams, S. N., 1995, "Erupting neighbors at last.", Science, v. 267, pp. 340-341.
Wilson, C., 1968, "Climatology of the cold regions: Southern hemisphere", Rep. 1-A3C, Cold Regions
Research and Engineering Laboratory, Hanover, NH.
Wolff, E. W., and D. A. Peel, 1985, "Closer to a true value for heavy metal concentrations in recent
Antarctic snow by improved contamination control.", Ann. Glacio., v. 7, pp. 61-69.
Woods, D. C., R. L. Chuan, and W. I. Rose, 1985, "Halite particles injected into the stratosphere by the
1982 El Chich6n eruption.", Science, v.230, pp. 170-172.
Zhang, X.-G. and T. M. Casey, 1992, "Long-term variations in the Southern Oscillation and relationships
with Australian rainfall.", Aust. Met. Mag., v. 40, pp. 211-225.
Zhuang, G., Z. Yi, R. A. Duce, and P. R. Brown, 1992, "Link between iron and sulphur cycles suggested
by detection of Fe(II) in remote marine aerosols", Nature, v. 355, p. 537.
Zoller, W. H., J. R. Parrington, and J. M. Phelan Kotra, 1983, "Iridium enrichment in airborne particles
from Kilauea volcano: January 1983.", Science, v. 222, pp. 1118-1121.
134
APPENDIX A
Elemental concentrations and related statistical information.
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Table A-2. Statistical summary information for the data in Table A. 1.
Variable:
Na
Na (*)
Mg
Al
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
97
52.96
34.97
34.84
40.15
1762.83
41.99
4.26
7.78
177.71
169.92
23.70
74.11
50.41
1.39
5.57
1.20
2.41
79.28
5137
97
48.35
36.10
35.12
38.38
1319.56
36.33
3.69
6.95
217.47
210.52
23.78
61.70
37.92
1.87
7.52
4.58
9.21
75.13
4690
72
5.88
4.83
4.56
4.56
16.58
4.07
0.48
0.26
21.89
21.63
3.15
8.11
4.96
1.58
5.49
3.78
6.54
69.29
423
97
15.70
11.03
10.70
11.43
240.93
15.52
1.58
2.26
94.68
92.42
7.21
16.26
9.06
2.84
11.42
9.63
19.37
98.88
1523
Variable:
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
Cl (*)
97
87.89
68.25
68.20
75.23
2952.25
54.33
5.52
21.89
301.06
279.17
50.31
105.01
54.70
1.59
6.39
2.45
4.92
61.82
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K
73
6.20
3.67
3.64
3.92
32.51
5.70
0.67
0.05
29.04
28.99
2.21
10.19
7.98
1.56
5.45
2.70
4.71
92.02
452
Sc
90
0.0009
0.0007
0.0007
0.0005
0.000001
0.0011
0.0001
0.000005
0.0072
0.0072
0.0002
0.0011
0.0008
3.59
13.91
15.87
30.74
126.64
0.08
Ti
73
2.62
2.21
2.15
1.80
5.05
2.25
0.26
0.12
11.52
11.40
0.97
3.28
2.31
1.77
6.18
3.86
6.74
85.63
192
149
Table A-2. (cont.)
Variable:
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
Variable:
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
V
Cr
Mn
Fe
89
97
97
95.00
0.03
0.02
0.02
0.02
0.0003
0.02
0.002
0.004
0.09
0.09
0.01
0.04
0.02
1.33
5.12
2.76
5.32
59.55
2.4
0.91
0.64
0.59
0.65
0.65
0.81
0.08
0.08
4.11
4.03
0.35
1.23
0.88
1.81
7.27
3.40
6.84
88.70
88
0.22
0.13
0.13
0.14
0.13
0.36
0.04
0.03
2.63
2.59
0.08
0.23
0.15
5.20
20.89
30.19
60.70
161.23
21.4
11.44
8.30
8.16
8.54
210.56
14.51
1.49
1.74
122.92
121.18
5.78
11.92
6.15
5.73
22.80
39.62
78.82
126.82
1087
Co
Zn
As
Br
56
97
97
95
0.0055
0.0025
0.0023
0.0027
0.0001
0.0097
0.0013
0.0002
0.0569
0.0567
0.0013
0.0061
0.0048
4.24
2.07
1.57
1.56
1.55
4.12
2.03
0.21
0.34
12.87
12.53
0.89
2.27
1.38
3.26
0.011
0.008
0.008
0.008
0.0002
0.014
0.001
0.001
0.122
0.121
0.005
0.012
0.007
5.40
0.21
0.16
0.16
0.13
0.04
0.20
0.02
0.003
1.06
1.06
0.06
0.30
0.24
1.85
12.96
13.11
21.70
7.35
19.51
29.81
174.64
0.31
12.90
25.93
97.97
201
38.44
77.28
127.03
1
4.30
8.55
95.70
20
150
Table A-2. (cont.)
Variable:
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
Variable:
Sample size
Average
Median
Mode
Geometric mean
Variance
Standard deviation
Standard error
Minimum
Maximum
Range
Lower quartile
Upper quartile
Interquartile range
Skewness
Standardized skewness
Kurtosis
Standardized kurtosis
Coeff. of variation
Sum
Mo
66
0.012
0.008
0.007
0.007
0.0002
0.016
0.002
0.0004
0.095
0.095
0.003
0.015
0.012
3.21
10.66
13.37
22.17
127.29
0.80
Cd
45
0.012
0.006
0.006
0.006
0.0004
0.019
0.003
0.0005
0.121
0.120
0.003
0.013
0.010
4.78
13.08
27.12
37.14
161.56
0.52
Ce
Sm
48
84
0.03
0.01
0.01
0.01
0.02
0.15
0.02
0.000005
1.08
1.08
0.003
0.02
0.01
6.88
0.0015
0.0005
0.0005
0.0005
0.0001
0.0084
0.0009
0.00002
0.0775
0.0775
0.0004
0.0006
0.0003
9.11
19.46
47.55
67.24
34.10
83.35
155.94
470.13
542.81
1.6
0.13
(*) indicates direct measurements on 1-2 ml liquid samples.
Sb
95
0.14
0.07
0.07
0.07
0.04
0.20
0.02
0.003
1.56
1.56
0.03
0.16
0.13
4.41
17.56
26.84
53.39
147.37
13
La
89
0.011
0.002
0.002
0.003
0.003
0.058
0.006
0.00003
0.553
0.553
0.001
0.004
0.003
9.31
35.86
87.43
168.37
553.18
0.94
Table A-3. Depth-age relationship for NBY-89 ice core (Osada, 1994).
Depth Interval
[m]
0.00-1.00
1.00-1.64
1.64-2.00
2.00-2.45
2.45-2.68
2.68-3.30
3.30-3.52
3.52-3.97
3.97-4.18
4.18-4.54
4.54-4.74
4.74-5.00
5.00-5.17
5.17-5.46
5.46-5.80
5.80-6.00
6.00-6.20
6.20-6.48
6.48-6.59
6.59-6.79
6.79-7.19
7.19-7.42
7.42-7.60
7.60-7.87
7.87-8.00
8.00-8.19
8.19-8.37
8.37-8.52
8.52-8.61
8.61-8.77
8.77-9.05
9.05-9.25
9.25-9.35
9.35-9.60
9.60-9.80
9.80-10.10
10.10-10.19
10.19-10.40
10.40-10.59
10.59-10.87
Date of Deposition
[A.D.]
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
1955
1954
1953
1952
1951
1950
Depth Interval
[m]
10.87-11.00
11.00-11.19
11.19-11.30
11.30-11.50
11.50-11.71
11.71-11.86
11.86-12.00
12.00-12.12
12.12-12.50
12.50-13.00
13.00-14.00
14.00-15.00
15.00-16.00
16.00-17.00
17.00-18.00
18.00-19.00
19.00-20.00
20.00-21.00
21.00-22.00
22.00-23.00
23.00-24.00
24.00-25.00
25.00-26.00
26.00-27.00
27.00-28.00
28.00-29.00
29.00-30.00
30.00-31.00
31.00-32.00
32.00-33.00
33.00-34.00
34.00-35.00
35.00-36.00
36.00-37.00
37.00-38.00
38.00-39.00
39.00-40.00
40.00-41.00
41.00-42.00
42.00-43.00
152
Date of Deposition
[A.D.]
1949
1948
1947
1946
1945
1944
1943
1942
1941
1940-1939
1938-1934
1933-1927
1926-1920
1919-1914
1913-1908
1907-1902
1901-1896
1895-1890
1889-1882
1881-1871
1870-1859
1858-1847
1846-1838
1837-1831
1830-1823
1822-1816
1815-1808
1807-1800
1799-1792
1791-1783
1782-1774
1773-1767
1766-1760
1759-1753
1752-1745
1744-1737
1736-1729
1728-1721
1720-1712
1711-1705
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ddv oanos uo iordun opiq stq XIzauog uumo joJan suqp 'JOAOMOH
(r')
'irqi os 'sio
~Ix]
+ [] [S] = [ID]
inuotwA.Isqo tuopui jo uoilnqjiiuo
jv
ptrq iq.u oql oi poppr zq piuoqs [A] xmntwu mo.
'swuwtu uoiunqjajuo
qi0o0lonp Z-'
"b oql jo op.s
u. 'MilFex
'a
in lirql giON "AJnaOF
odsoa
;ai3nos pue uonisoduwoo aanos paollr
am [7] put [SI 'OaIH
[1] [s] = [I]
(Z')
.10
:
s!
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a:
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.
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1
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a jZos
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uoissino oamnos 3i3o.ds r wluuomol ur jo uo.lTa1uuo0oo 0q SM•OqS 1i zoous 'uorloTwJ~iuopi
ol I AIlnumnb j•otskqd Injosn - St S aoiotuw-id ot,
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f
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o qA014m
•
amanos 0q1 m1ouop I pu' 's'1 snau0o 0l
ms
fos 'lqgaiM
jo jaqtunu put 'tqiuao.
fy1 .YsS +........ +f F. !s + Z1.Z s +f 1t.is = o
(Q"I)
(9l)
161
114D "11]
= [1-H
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ST XLIUJU a0U'UhAO3 Oqll JO uotflljsuoO3 OR1 ol •AM •nluIts r u.pman1Jsuoa st [ý' XLIWtu
uo•Ia ooo i 'dals suji ioajj
"l1un auo aoq I•M os vip aotp Jo aotUmmA Iloi aol4
ol luatuala
qt0a Jo uorlnq!.lUOO oq4 'aOojoajoaU
UPa Atq SUOI.1.IUZOUOO
L
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"auo Jo UOITiAOp pMpURIs Vput onaz jo QnVlj
paz!pJUpUMS
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ail Aq pnsoi ow ~uTpIAip put ,oa alqj'.UVA aql ti lmod mltp qmea uio.ij aoqgýMA aql jo
unatu aol •uri.rmqns Aq (uo.vzpplvpuvs sp uMout
osIr) uaul agqt
inoqt to 'MOo alqO.UnA
irq1 I Slulod lvp a0q [I jo samnbs a4 jo tuns 4oqJo looi oainbs aoql q M•o
v
ut iUod VJVp qORa BuIp!ATp
zjqt.MeA
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iq oaql inoqv auop aq Jaoqtoa
uo uoyvzvlmUaou aoqL
•xuPtrU1 MUp MEJ aql Ut sajqnuPA jo UoiI•ZlUUou aql SaAIOAU.
daois isnj aoql 'suoTpuo03
asOti1 AJsnS IOU Op VIVp Oq4 J1 'AioA!nTUJaMV "xUWtu a0q jo osodsuma a0z4
smouap ,£a0JM
j[D] [L] = [,]
(g')
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s9t [J XulnuV
oqlJI
a3URUVAO03
uTaq1 ioj suolIpuoQ
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0
oqi
js1srs mlp MrJ
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AroTadsaj 'soo.Ultu (aldturs) utunloo pu (luatuaolo) moi a0J [1 Pur [Al] aaoq1M
[10 [1] = "[j]
(P'1)
:st UaoIum,aq osi, utro N[j] X.WUI mP
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JO Slaun lUa.Ijjjp q•.aM sOjqIt.MA apnlou " mlp oql uaoqM daois kmss00u r sT uotzltmuou
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l) siuiod virp a0ji jo lOArJ U!Spq I•nqimsns
:SI3VJ OMI LuoJJ
jo amJflu JUr.mAU. 0leos a0q4
a04 put '(Z661 '"Iu 10 vtPJmN) anbniqoa a0l4
sauooo iTssaoaou stiUJ
MtAJ oql Jaoq4aqAM
"A1XA
aotuOS Ut PaZI1•Uuou oq plnoqs Jo st sr pasn aq uro los ri-p
oqt,optnu aq plnoqs uo.sTOap t 's.sAltuu a0q ~SutJms aOiojaq '.OAoMOH
'(166T 'AluaH) sjOnj1 Jo iaqwnu tunununu r Aq paq.idxa
oq ue:3 mvp PlIvamalu.
Z6I
'(6861 'u'o"I UBA pue qnloD) uaoaail uoyisodwuooap viijAads ojl ol Sutpaoo0V
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*suoitluuoJJsuiJ1 ouo-ol-ouo opun
uum
L
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OaR sIJOILUTISO pooqIo0)I
e.xLtu 041 put 'uonounJ ouo-ol-ouo r Jo soumw Xq [] o0l po0ilai a0J[o ] jo slne02AU•0.
pur sluouodtuoo Ijudiupd
olp wtpl ioj oqT Aq pooluamng oslu st uonnlos slp jo ssouonbrun
OtL "uoloos sql u! zxow Jz1IlnJ pguLU~x0 Nq l 3lom
J stu.tL '(661 "771 10PJNlW)
7
(suoilwAosqo UZATS otq Jo poo•Iaq
I 04l oziu.rxtLu 4r0AT sa0outtId otp Jo sTnlA)
saJotu•w
d uo!ilIndod gmuipuodsoaoo ot1 Jjo sWoIupso poo4q)I1 umuiru 041
.i
s0nflAU02t puE (s.o10oAUo02o) sluouodtuoo Idiouud otdums oZq nip Imuou oj 'ploutisi
oan [e] jo sonIVAUO.To Oql uoaM lwtql ioJ Zip 0 o np sti st4tL "sJo33jjo aoquinu tunusp
v Aq poutildxo oq IFi•M
A los
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sp
[=]
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.
pMtnl;,JJUI Jo 03UBTrJA umufxUtu oql
01
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ninp MAthi ql
Jo uotISUOLUIp .130ltus Oql o0 1U01VAimbra tunxuw rxq l4AM
'[''] JO jri oq0l s. b jo onlA OtLL
([Ufx
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(u'Cz)
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b SXY.......
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Oq u73 11 IM41 os SJ0IOOAU0•10 JO loS r oiUt [-•] osodtuooop o0 si dols lxzu 04L
"(jaOM 141 ui soldurus) suoInmoasqo Jo aqtunu zql s0louzp
uI OaOH
(t,861 '"I' 10 IAMOaUH) xl.ntun VVp POZIuJOU 04ql Jo S10133A MOJ ulrp 0ql uoaaomq
S0Jg1U Oql JO SOUIsoO Oql o1JU0VAfmbo xL1lntu uoI•lawIuoO
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X.JiLU vvep Mri PozipipPUm1S
0q4
urtJ 041 jO SuLuOIO 0ql
lnsoJ 041 jo Uou•aj
LUOJ pouitlqo si xUntu
pOztUIJOu 041 JO SJO130A MOJt RPp ol41 uoAtmoq sOIUt
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XUl.
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4
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uoitlOJaoo oq0 JI "x1JPu.
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0T4 Jo uoltIzlzuuou Oql sOlouOp AN aOoqaM
U
(t t'a)
(o01)
E61
u! slinsOj 6"i "bg2uisn pur L[j] Aq II'IcIba uAld•innl
I
[r3] [a]= [•a]
Q I *C[)~
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1
,1[
1 3j.b] -J[] [a] = [y]
veql punoj si M!'6"U "bgtuisn puE 8"1 "bg oiui 9"1 b' ~trnninisqns ,q
(6)
j[l] = -[q]
a 'qapao
oIqm
•siInsoJ
'idaodoad •XiIiuo2oqlao oql uoaj "uoipos silp ui int I pzumldxz oq
UO
aqipooi. poonld arm sonIVnuo020 OSOU T
muiseo.oa
p v in ['yj xmntruo
muotu odxo oqi jo ainwlu
jo uoTIOuT1Sip
oIs!iWs oqjt
q pooniuamnn
isouq[
st sonlEnu0aU1
OL "aoJq pOaNOIAW oq iou I•m put oanniviu oqi ul poqsqtlso IloaM OaJn
WIq1 spoq•iu OAIVaOIi snOIrnA Aq poumlqo oq uro [j xmntiu
Amnitu oq IBM SJO133AU0o21
OSOq 'pOziUtuou s91
funr.su
LL "qmju.iouoquo
pur 'IjUuo0oqJo sT [j] OOUIS
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o0 I-nbo 2rtoq [[j xrntuw Autnputns zqp Jo SMoJ oqi tl!m 'uonnflos
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onbru nL
oql nU JI -XTLIuW ltuogoqtPo ur ponuo st [I] pun 'uonttuUojsU.n iEuo~o2 o uo
pollo si uo.raodo siujL "uorwado uotnzqruomrp sup Aq p-u3rqo ar [] jo sonluAAu o
4oq'sonlInAUZI; si oq oslr '.~ [JO SoLUouomlo zq wuS "oures oqj4av sonljnAU02!
lay;tI put 'sooatultl
JU!WI PSIpolloav [
(gcz)
pu[y[-L ;)LL "x. lnut -euogrp r s [y]J aloqm
[•]==.[J][-][a]
vqi os [j]
A1iClfuris v Aq poziruogrip oq tum 'xuWltu oflnotuuvs
xIlutu
n sqo qmljtM
'[] x.Jlt uo lUlTJJo3 qtp
SJoi13oj JO Joqunnu uwnwlunx
oqiSOA1r
t,61
u Jco13turJd 1.iwu.
Jddn uouwwtuns oql w3qi
o1oN ,oAil3aodsoai 'sluiod impp xulvw uuwnlo pu- x.nuLwu AxOJ o
[=f
(9['(I)
•fgf n fi'm•
(9vO:)
=
olvoltnpi.
puL A osoqm
IV0
U
sL Uoi.UAm oq u-e xlun-
ewmp pozl•uuou oql Uiiuiod vwp L ',XpiiTu!S
[=f
(sj'(1)
A-lfnfs
X
=
2
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U
su U3IiiAi
oq U~3 1ii uoql '3ads JO13)J op
'[3] xuwai itp M
cu
oql
tUTJ013OA P
Su pojaopsuo3 Si 'E'-
"b3 •q pou'jop
iuiod irpp ~jj "ooads lOiouj srpl urds •qi '"'12 ......
' 'Izf 'tI
.fln Irtwouoq1jo u ougjp ol olqlssod oste si
'SJO13A
I
31l ut aoufisop uunlo, pu 000uiSOp MOJ I-qL 14ITMA
pM)O.oss
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poziTtuou
wnlup 31q1 Jo fnlLA 31l4
S;A1i J0130A U oliuo iuiod - Jo uo101ao[od oUtLL "aodsjloinj s.UP u. muiod v Xq plu3saiJda.
aq u-a (aldaus) 'u•isap uufnloo qtia
pozi•tLu
ou atp jo (iua;u)w3)
pup 'do•idA e sv paaoplsuoo aq umo xJtIui m1p
u2uisap AOJ 4tea3
11vql
os poujzp Si oands ioiJ3J V
:(0861 ',JaOmH puu .qsmouT.•u) smojIoj sp luiodAOMiA Jo130A PWoIj pOu1jedxa aJ1oq
aq uro uoilisoduwoaop xultu Jo 1doauoo atJ "xluw urip pazrtuou oql asodtuoaop ol
'XlOla1oodsaJ 'sa3lIuJ uufnloo pur A•O•
pql
oj suoiss;adxo pyT[A O.M tI-'1 put ýI'-j "sbg
',[]= [A•
(•I1)
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u)
(vi
pu.
SaATZ I"1 puT iTC" "sbH jo uosurduoo3 V
(z-I(1)
[31] •1[i] = N[3]
oq
(61 ()
96I
iuql punoj s! 11 '6-'CI
pup La "-usbg uuPdwo,-
uux
1=1
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[uUX
............ +
[ux]
!UO
Jux
[ux
UIx
[U x
JJw
[Jr]
7
ZJx
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[ x]
1 kg,;=[/]
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[Jx
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uuo xLPwu uoilplauoo oql '[ UX ........
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=
[d] = [AA] su E 'I
"b3 ~U!UhUJo-
(s8u)
U U
su u.ajuim oq uro uoiwnbo sul 'sJoOOA iiun oqq jo
Xnladoid ,iili•uuouoqlio oqi ~umsn pWe LI'
"bg olu 91'-a "bg 5u!ulnsqns •q 'axojaoiLu
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(LVU)
7l
sr umaum oq upo xulrtu supJo luotulo up '9"g-C
ubxauL
Xw uon1laiuo3 oqi Jo
soldturs Jo Oqwunu j.ai
uopiulfop oqi uno.iq "amouird
y
oq Xq XlsnoiAoid poirugisop su•
OTl p~U
sitp •q poamOle (sooanos)
'(xuvwu uoiaO.UO•3Qq jo jpuml
. Oqi Xq pao!ur.) onbriaqo
961
OATSSo33lns qS o Os 'joJJno inpsaoJ 1pro uo poqiow saonbs isroI
oRi Xq poialnou X{OA.pnaosuoo oq um3 SJOlOAU091. 'daois tlo
(zz'(I)
(Y) :NO
ui JOJ.on
oqi jo uoluollddu
sui
azru..luu oJi
No
[=.
- No = (j)
,~J.18m
a
SU Uollum
oq uto iaaoulwtd ioj.ao I[npsaoi stp '(sluouodwoo Ipediouud) sjOli•J y lsjxj ;tl
Xýq auop si uouonpoaidai oqi jI "lddlIunoo poanpoidoa
Jitsn
sii pur lmrod erip imuoauodxo
u-r uooAoq auoao;jjlp oR1 su poutjop oq uto a oalou•mud JoJao Ipnpisao V
:(0861 '"aWmOH puP .qsAmo.I1N) SAHOflHoJ sr oaornj pouTwuxo oq
mou uP
L'a "bgJo uJ.uoj Otl cuI xu~nu uoIlwJauO0 Oql osoduoaop ci uosFai otL
01 gLupJooo-3 JlouJ L uT SOJOOS
"3OuoaoJai
pus oJiz jo
LnrmA
J3S
s LL "auo Jo UO1.WIap pgwpurs
Joioqaql aJiudwuo oi sdpi; )qlas
aOSh.IOAUUu• OaI4 [.AX soaocs o01IOJ ol 'aojOaqj '(EL61 'i6"OJuoD) sao.Is Oql Jo UOT.1TAOp
p.wpumls oqi •q OauOaJJIp Oql
.UTP.AIppU Pao3S A\mi pIo
a
Ifoj onlJeA OagJoAr I.o!
Sui.nilqns •q sawoos lmoij oziparpuris Oi o.•plrld jaouo2 oslp si 1I "odurms otl Oi jolo•j
lIM1 Jo UOcunquliuOc
otl 'spiom aoqlo uI
OTl lI1l IoN
OAzLIIOip1J
i uosaidoa
jlioJ gToads r ioj odtums v jo aocs JOlouj
ssaldures art uo sluuomuoioddr oainos qi1 lUosoidad
-7 JO13OA McOJ Mp Otl uo fJO1OOAU;%.•
OT4! Jo
otmiiodui,
saicos Joinj
oq1 jo ains-aui
USI O13aOAUOBO qoo uL
tl'x inmonmrd ooairti (tI'(I "b!) uoulnbo oamrs oqt tuoij uoos oq
uga !. ',qxelIu.S "•" jo ooumiaoduIn
OA1WJlOJ Otpl 0 JolW3Ipu.
ur si Ai flJnlAUaia
0qp '(vi'(
"bg -os) fX JO13aAUo2!i Oqocuo . xu3isop uwunlo oqi jo uoilool3od Oql sI (JaloOs POllO
osle) ?f. olmouwawd Oql Oui.S -TX Ji3o~3Au0.0 cqtl
([')
lATM
paPQ.OOssV OnlJAU03.0 0t4 SI
0JRA
O..
[ufx...... (fx'fx'Ufc fX x]=
put
[=t.
(0oQ')
= 'y
wL
L61
u.•lqo uro ouo g'Q "b3 ui uoiluoJp oqi Su!sn put 'LZ'I puu 'tZ'Cj
"sb3 wuotI
(LZ'Cl)
Iro
r[ ]IX
ui salnsaJIx Aq 9Z'T "bI jo uoiwmoidintuaid
(9•'G)
uDX + ........ + ZDZX + IX
= [ND]
St SJO3OhA ZSgtl
Jo sturum u xurntu 1?Wp pozit.Iuuou oqjl onuM
ol olqlssod osjr s. I ".OiooAuo!ai lsJJ Dql
TIX pu '[9] XLllU Oql JO o0130a
Mo.1 IS.•.J
(sz:a)
a sT I'.......
[STt
'crg z] ,]=
Tx
19 oioqm
= rDE[NA]
s'e uuoj xutLu ui uoluM oq uro jZ'(I
bg 'u oi i uoij SOUVA i .•muemird oqi pu- "fx = f!m wqi Ouupqui-onia
pupe OZ0'u "bgSuisl
[=.
[=1.
rQ X!M= 3
(t~z)
JINO1
U,
U,
UT
salnsaoi CZ'
0-
(Ev~a)
"bg ut ZZ-' "bgRuTs1 l
m
:uo!lnbo BuiMolloJ oqi ADqo oi poioodxo air siolonjoo
amoi
t o iroodsai 4lM (i)a
snaloturad onao oqil Jo soajnbs ;n4 jo SOAnUauOp oql 'IaOOOAUOStO lrditouud isiU oqil urlqo
o0 ',j uipioooV
e ioj sunoom
"lsm1up 4oql U uoteuA oq4l Jo LunmtuJ
lJo30AUW2t0
(a'CI)
86I
7x 6X = 6x ,3], []
siag ouo 'wE'I pup OE'(j "sbg tuoiI
f=[J']Lx
(*o)
u, sllnsai
fX Aq
I 'C "b"jo uourouIdintuiJd
+
'X ........
u Uy~~
+ EIOX + z _ZX
(wu)
(~a),_;9
'D[x [ANI]= '•]
st uOllum
zq uro qoiinA 'siona Imnplsai lsnj oqj jo posodwuoo xi~rtu lonao uLxu up s!t[3 ] aioqM
(oWu1)
Zx
= ZD I[g]
ui sllnsaJ sTUL "oJaz o0 SOA.lA.UOp Zql Jo inns owl Surlls puPlPulsuoo ([Y'a Su.dooll ollwq
Jo uo nTuZIu.u 'oagojoaoLIJ
oi poqloui sowunbs isvol oqj g.usIddr Aq pAoarq: si Omuox
(y)':a
(6Z'a)
_(r)a =
zg
(Z)
1.1v
j! NO-
=
(Z)
did
Aq UOA! S J•aUO mnp~sa puooos oqL 'A•~M ours oqlJ uI
•IIp Oql jo ueuLIA Oql jo IsouI .oj siunomv pup (os poirugisop AIsnoTAoid) OnlEAUO!O
Is0a91I Oq4 ql!A pMW!OOSS- ST JO130AUOSTO ~gdomuud isnj oqtl Wq smoqS llnsoaJ su.L
([x[ =I []
(gzci)
661
"O3UtI•I•A
unnurxeum oql umldxo I. (siuuodwuoo) SJO1AUS!O •dioui.Id jo azqunu mnunun
ui
oqi imp os XuM I•rundo uur
bj
muosaidai 'L'CI
ds mvnp atp jo soxy mauipooo oqt
u! posn 'SJOIOAUOS!I I•tUOUOt1uO XUtmnui jo los onbiun qoqi M04s
oqisuoIVInolo SOtsoLL
[=/
Y+fX r+[y = [+fQ [•,]
(Lwa)
i~'_x 'x~l
-[_=l] []
(sE•a)
puts
:suogpnbo pozi.tumo
BuTollofoj oql utsnfAq ,Xvm oures
Jo
30UMMIA uUiMturaZi Oql jo
ISOAIL' pUOOOS OqL
wsoTu
U.poutm
toq
Toj
qo
oiv
SJOP1A0jAUS•TB
~UTUIuJJ
.•l•
lj p ;qi
slunooo• pue (os pOwuS!szp AsnoiAoid) OnflAU0g!O
LJUM pOIW1OSSE Si JO1OAUO!TO edimuud puo:os ozp 'aoloaotjLL
(9ga)
ZX ZY = Zx '[u]
ui sllnsa EE'(I "b oiu!
'Ci "b3 2uT~uosuI
1x'x [Y--]= '[•]
(Eua)
su~tlqo ouo '[•I
tijol z
xultwu Inplsz' is.~j oqi su uontnbo sup jo apjs ptnq
a
l .ugmujzp'putm 'uouiiM q uwo
rx byJNY
- D][ ]= g[]]•[g]
pue 'I
'Cl '9Q 'gE'C "sbg tuoj_
uoiTnbo oqi 'D IID t= Iy dtqsuo!ilai oqi1
W1q4 lOS
VJVp
OtJl JO Oou
Ajo sJO
Tun
00Z
s•l iSaIlorj u ut sluotUolU
J lioj sulpeol .ol:
j
painbs oqi jo tuns oql 'axoJo.otj '(0661 'zOtu1O pPUP utMUOH) .xo1o3j o3q jo 3.rLeA
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Oq
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OE <-'-OZ
W:°N
zO + zOH <- 'O + HO
ZO + OlD <- lO + ID
HO + 1 <-- At + IDOH
'O + IDOH
<-
OD + zOH
:tusiurtqOu OID/ZOH
ZO+0-1I<--10 + is
kO + OID <- £O + ID
ZO + ID + ja <- 010 + 0•[
:usnr•STUlaur
zOý -- Oz
OID/Oia
:lN
ID0013 <-- OID + 01O
( ZO + OID -- lO + [D) Z
O + IDO001O
<-001D + ID -- A't + [D001D
LOZ
'(i) Z~ONOD - (2) ZON + (9) 013O
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smq 'uo.ppg uI
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'(s) OZH + (S) 3ID- (s) D13H + (S) D30H
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s pu
S oajoqm
(s) £ONH + (S)IDOH <- (s) OzH + (S) ON13O
pute
(s) £ONH + (2) ID <-"(s) 13H + (S) zON0O3
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J
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o
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(s) EONHZ <- (s) OZH + (9)
£OzN
'pue
(I) ID+ (2) ZON <-- Aq + (2) IJZON
(s) 'ONH + (3)lDON
*-
(s) IDH + (2) £OZN
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