Review of 2006 GCOS Satellite supplement
Lawrence Flynn, NOAA
3.1.7. ECV Ozone
Ozone is the most important radiatively active trace gas in the stratosphere and essentially
determines the vertical temperature profile in that region. The ozone layer protects the Earth's
surface from harmful levels of UV radiation. Since the 1960s, stratospheric ozone has been
monitored in situ by wet-chemical ozonesondes, and remotely by ground-based spectrometers.
Since the late 1970s and 1980s, ozone has also been monitored by optical and microwave
techniques from various satellites and ground-based stations. Atmospheric ozone amounts
declined in the upper and lower stratosphere over the 1980s and 1990s, and remains at levels
below those present in the 1970s and earlier, largely due to anthropogenic sources of halogens.
The following is required for this ECV:
Product A.7 Profile and total column of ozone
Benefits
Products will support monitoring and assessment of:
• the impact of the Montreal Protocol and its amendments on the anthropogenicallyinduced removal of stratospheric ozone
• the expected radiative influence of ozone on the climate system, and its role in the
chemistry of the climate system
Target requirements
• Accuracy: 10% (troposphere), 5% (stratosphere)
• Spatial and temporal resolution: Horizontal: 5-50 km (troposphere), 50-100 km
(stratosphere); Vertical: 0.5 km (troposphere), 0.5-3 km (stratosphere); 3-hourly
observing cycle everywhere
• Stability: 1% (troposphere), 0.6% (stratosphere)
Requirements for satellite instruments and satellite datasets
FCDR of appropriate UV/VIS and IR/microwave radiances, for example through:
• Nadir UV/VIS instruments for total column and limited profile information
• Nadir IR sounding for profiles from lower troposphere to stratosphere
Supplemented by:
• Limb sounding in IR/UV/VIS from solar, lunar, and stellar occultation
• Limb sounding in IR/MW/UV/Vis from atmospheric emissions and scattered solar for
profiles from upper troposphere to mesosphere
Fully achieving the target resolutions will require three low Earth orbit satellites, ideally in
combination with five geostationary satellites.
Calibration, validation and data archiving needs
Comprehensive ground, ship-board, aircraft and balloon-borne measurements are required for
calibration and validation, for example through:
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Review of 2006 GCOS Satellite supplement
•
•
•
•
•
the NDACC (Network for the Detection of Atmospheric Change)
the WMO GAW network of ground-based total column ozone measurements and profile
measurements from ozonesondes
the WMO GAW and NASA/SHADOZ ozonesonde global network
the global networks of Dobson and Brewer instruments (and their operation in Umkehr
mode) reporting to the WOUDC
the MOZAIC/IAGOS commercial aircraft programme
Adequacy/inadequacy of current holdings
• Total column measurements provide largely adequate data record of gross change and
fluctuations
• Profile information is sometimes of limited resolution and often lacking in long-term
continuity
Immediate action, partnerships and international coordination
• Reprocessing of identified datasets by improved retrieval algorithms, especially with
regard to instrumental biases, including effects of ageing in orbit
• TOMS and (S)BUV provide an established data record from the late 1970s onward. HIRS
provides an additional possible long-term record, to be supplemented by present and
future data from high spectral resolution IR sounders. IR data from operational
geostationary satellites are also available. Shorter-term data records are provided by
instruments such as MLS, GOME(-2), MIPAS, OMI, SCIAMACHY and TES
• Reprocessing of occultation datasets, such as from SAGE and HALOE
• In addition to the opportunity for reprocessed products from particular instruments or
series of instruments, there is an emerging opportunity for provision of integrated
products through data assimilation
• Continuous research and related intermittent observations are necessary to fully
understand ozone chemistry in the troposphere and the stratosphere, including precursor
trace gases
• Coordination by WCRP SPARC, IGBP IGAC, IGACO Ozone
Link to GCOS Implementation Plan
Activities identified here will contribute to GIP Actions 25 and 26, which call for the
development and implementation of a plan for a comprehensive system for observing key
atmospheric constituents, including their vertical profiles.
Other applications
• Use in NWP and air-quality forecasting
• Monitoring and assessment of UV-B exposure at the surface, with its effects on human
health and the biosphere
• Monitoring and assessment of exposure to tropospheric ozone, with further effects on
human health and agriculture
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Review of 2006 GCOS Satellite supplement
Ralph Ferraro, NOAA
1. The CMIS sensor is no longer an option, but there will be something similar forthcoming
from the revamped NPOESS - DWSS; so I suggest references to CMIS be clarified or
caveated somehow.
2. On page 21, there is a statement "...arrange for a TRMM...follow on...". This indeed is
happening through the NASA/JAXA GPM (Global Precipitation Measurement) mission,
which will be launched in 2013. So this statement should be updated.
Mark Dowell, JRC
1) General perspective across ECVs:
a) There need for a clear statement on the difference and applicability of the requirements in
the Sat. Supplement (GCOS 107) and those provided in the WMO tables (under climate).
The latter has the target, minimum and goal whereas the Sat. Supplement only has the
target (??). I see different agencies using one-or-other of these in defining there
programme requirements.
b) sometimes there is a feeling that the ECVs requirements are specified with different
levels of stringency. Some being more conservative that others. If one looks at climate
modelling from a holistic point of view it seems some of the requirements are too strict.
c) some clear traceability of where the requirements come from. I recently learned that the
requirements supposedly cover a range of different climate science applications (i.e.
climate modelling, climate trends, other climate applications). It would be useful to learn
how they combine all of these to come up with the definitive requirements and maybe in
some cases subdivide these per eventual application (see OCR example below).
2) From the OCR-VC perspective:
This is sometimes a bit confusing, it is our impression that sometimes the requirements are based
on Water Leaving Radiances whereas in others it is based on Chlorophyll "a" concentration.
Hopefully based on the new definition for the Ocean Colour ECV in the revision of the IP we
can now provide more specific requirements. This would eventually be provided to GCOS
through the IOCCG as the body providing scientific recommendations. I provide, attached, a
VERY early draft of what we are working on. Please don't consider the content too much at this
point, this is merely to illustrate that we will divide our recommendation per application area and
distinguish between water leaving radiance and Chlorophyll.
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Horizontal Resolution
Parameter
Units
GCOS 107
WMO Tables
IOCCG
Climate Model
Ocean Colour - Water
Leaving Radiance
mW·cm-2·µm1·sr-1
1 km
1 , 5, 100 km
4 km
Chlorophyll "a"
mg.m-3
1 km
1 , 5, 100 km
4 km
IOCCG
Trends
IOCCG
Regional Mod
IOCCG
Trends
IOCCG
Regional Mod
IOCCG
Trends
IOCCG
Regional Mod
IOCCG
Trends
IOCCG
Regional Mod
Observation Cycle
Parameter
Units
GCOS 107
WMO Tables
IOCCG
Climate Model
Ocean Colour - Water
Leaving Radiance
mW·cm-2·µm1·sr-1
1d
1, 1.5, 3 d
1d
Chlorophyll "a"
mg.m-3
1d
1, 1.5, 3 d
1d
Accuracy
Parameter
Units
GCOS 107
WMO Tables
IOCCG
Climate Model
Ocean Colour - Water
Leaving Radiance
mW·cm-2·µm1·sr-1
5%
5, 8.5, 25 %
15%
Chlorophyll "a"
mg.m-3
5%
5, 8.5, 25 %
30%
Stability /Decade
Parameter
Units
GCOS 107
WMO Tables
IOCCG
Climate Model
Ocean Colour - Water
Leaving Radiance
mW·cm-2·µm1·sr-1
1%
1%
2%
Chlorophyll "a"
mg.m-3
1%
1%
2%
Precision?? (probably not)
Parameter
Units
Ocean Colour - Water
Leaving Radiance
mW·cm-2·µm1·sr-1
Chlorophyll "a"
mg.m-3
GCOS 107
WMO Tables
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IOCCG
Climate Model
IOCCG
Trends
IOCCG
Regional Mod
Review of 2006 GCOS Satellite supplement
Manfred Gottwald, DLR-IMF
General comments:
•
•
•
•
The traceability of data is not explicitly mentioned. This is especially important for
higher level products (> level 2) and might be worth adding.
Are there references for the sources of individual requirements on ECV accuracy,
stability, etc.? If they exist adding them would be an asset.
A few statements about the consistency of data sets and external inputs could be useful.
Is it foreseen to add something on interdependency of ECVs?
Special remarks:
•
•
•
•
•
Executive summary (table 1) and table 5 on page 4: since CH4 is not explicitly listed it
might be worth considering including it in the list of ECVs in future (other GCOS/CCI
documents mention it)
Chapter 1.6.1 (page 5): A link between FCDRs and 'Product' (as used here) and the
associated terms 'level 1, 2 or value added' in remote sensing ground segments could be
useful.
C.1 b (page 8): Requires on-ground measurements with better accuracy than spaceborne
measurements. They also must provide better or equal spectral resolution than the
instrument under investigation.
Page 27 (immediate actions .....): Perhaps it's worth mentioning the possibility of data
gaps, e.g. after ENVISAT and how to overcome this situation.
Atmospheric Reanalysis (page 29): Consistency and interdependency of the data are
critical, i.e.
- Are the data to be combined dependent on each other?
- Is it ensured that additional data add information?
- Are the auxiliary data (e.g. climatologies) consistent and independently derived
from the data to be analyzed?
Dave Young, NASA
CLARREO related comments on Systematic Observation Requirements for Satellite-based
Products for Climate – Supplemental Details to the GCOS Implementation Plan
General Comments:
The CLARREO mission is not focused on a single ECV, but will provide benefits across many
of the areas identified in this document. There are several reasons for this:
1) The CLARREO suite of measurements is designed to provide an integrated view of the
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entire climate system. In particular, the CLARREO measurements are designed to
provide information on the most critical but least understood climate forcings, responses
and feedbacks associated with the vertical distribution of atmospheric temperature and
water vapor, broadband reflected and emitted radiative fluxes, cloud properties, and
surface albedo, temperature, and emissivity.
2) This approach deviates from the traditional deconstructionist method of understanding
the parts to build the whole and takes an integrative approach that measures Earth
system-level indicators and uses them to draw conclusions. CLARREO is not focused on
instantaneous retrievals in the classic ECV sense. But it is focused on the goals of the
creation of FCDRs of the ECVs that will be used to detect decadal scale trends in these
variables.
3) Finally, CLARREO will be a significant cross-cutting component of the climate
observing system due to the capability of providing a reference intercalibration standard
in space. This with enable the ability to achieve the accuracy and stability goals of a wide
range of ECVs that use the vis, NIR, and IR spectrum. In fact, CLARREO will provide a
means to achieve accuracies sufficient to break the current reliance of the climate system
on stability and overlap.
The CLARREO measurements address the following elements listed in section 1.2.
(Basis provided by the GCOS Implementation Plan):




Characterize the state of the global climate system and its variability;
Monitor the forcing of the climate system, including both natural and anthropogenic
contributions;
Support the attribution of the causes of climate change;
Support the prediction of global climate change;
Specific areas where CLARREO fits in the document:
Section 3.1.2 ECV Upper Air Temperature
Measurements from CLARREO
 High-spectral resolution IR radiances for use in reanalysis and
 GPS radio occultation;
Benefits related to CLARREO

“Monitoring and detection of temperature trends and variability in the troposphere and
lower stratosphere”.
 “Validation of climate models”
o CLARREO will provide direct information on lapse rate and water vapor
feedback
Accuracy

CLARREO’s goals is to produce accuracies of 0.1 K (k=3) for the IR radiances. This will
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enable trend detection through both the CLARREO data record as well as through
providing a reference intercalibration of the IR sounders.
Section 3.1.3 ECV Water Vapor
Measurements from CLARREO
 High-spectral resolution IR radiances for use in reanalysis and
 GPS radio occultation;
Benefits related to CLARREO

“Determine radiative forcing due to water vapour and the nature of the water vapour
feedback as greenhouse gases increase”
o CLARREO will provide direct information on water vapor and lapse rate
feedback on global, decadal scales
o CLARREO will help address the stated accuracy and stability goals
Section 3.14 ECV Cloud Properties
Measurements from CLARREO


High-spectral resolution IR radiances for use in reanalysis
High-spectral resolution NIR/VIS radiances and reflectance
Benefits related to CLARREO


“Cloud feedback is considered to be one of the most uncertain aspects of projections of
future climate, and is responsible for much of the wide range of estimates of climate
sensitivity in climate models”
o CLARREO will provide direct information of cloud feedback on global, decadal
scales
The text states that the this ECV requires, “Long-term products: exploiting the
operational meteorological satellites, combining at least two stable- low Earth orbit
satellites, carrying VIS/IR imagers and infrared and microwave sounders, and five
geostationary satellites, carrying VIS/IR imagers and some infrared sounding capability”
and “Validation against active ground-based and space-based observations is needed”
o CLARREO will provide the reference intercalibration for the VIS/IR imagers and
IR sounders in order to achieve the accuracies needed for decadal scale FCDRs.
Section 3.16 ECV Earth Radiation Budget
Measurements from CLARREO
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

High-spectral resolution IR radiances for use in reanalysis
High-spectral resolution NIR/VIS radiances and reflectance
Benefits related to CLARREO

“Insight into the response of the system to changes in its forcing and feedbacks (due to
changes in greenhouse gases and other factors)”
o CLARREO will provide a decadal record of the global, integrated climate system over
the full reflected and emitted spectrum.
o CLARREO will provide improved calibration for CERES and its follow-on missions.
The combination of CLARREO and CERES will be needed to derive decadal change in
cloud feedback.
Section 1.6.1 Data Records and Products
Section 1.6.2 Accuracy, Stability and Resolution
“In this document, the term ““Fundamental Climate Data Record”” (FCDR) is used to denote a
long-term data record, involving a series of instruments, with potentially changing measurement
approaches, but with overlaps and calibrations sufficient to allow the generation of
homogeneous products providing a measure of the intended variable that is accurate and stable
enough for climate monitoring. FCDRs include the ancillary data used to calibrate them”

CLARREO will provide in-orbit, continual, long-term reference intercalibration to
improve the accuracy of IR, NIR and vis imagers and sounders. This impacts a wide
range of ECVs in terms of instantaneous accuracy, but more importantly, for accuracy
stability and intercalibration across multiple instruments for long-term climate data
records. CLARREO will contribute to the calibration goals of many ECVs including:
o Upper air temperature
o Water vapor
o Cloud properties
o Earth Radiation Budget
o Albedo
o Ocean Color
o Aerosols
o Leaf area index
Section 2 Cross-cutting needs – providing calibration to SI standards per GSICS
This is a main objective of CLARREO. The CLARREO mission design is based on the
principles described under “C.1 Comprehensive and routine calibration of satellite instruments.”
CLARREO is coordinating with GSICS on the use of CLARREO for reference intercalibration
to provide traceable calibration to other space-based sensors.
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CEOS SEO Response: Brian Killough, Shelley Stover
1.) GCOS-107 target requirements in section 3 are directed at in-situ and/or space observations.
There is no way to allocate a single requirement attribute to space or in-situ. Therefore, a
statement to this effect is needed in each of the “Target Requirements” sections. Also,
suggest that a statement be included for each ECV in section 3 on state of the art in-situ
availability. Explain to the space community what exists for in-situ observations and let
them derive the goals for space instruments. Also, address key technology needs for each
type of space instrumentation that would enhance a measurement.
2.) Emphasize to the space community, as in page 26 of the GCOS IP, that they should focus on
using gap analyses to identify other missions/instruments to coordinate with to meet
requirements, if necessary. In addition they should focus on using calibration data for
various instruments, especially CLARREO, to increase accuracy of the measurement.
3.) Identify/suggest metadata standards that the space community should be using temporarily
until Key needs 10 and 12 of the IP are fulfilled.
4.) Continually state in the IP that the space community needs to make measurements to SI
standards but no specific standards are cited. Be specific in the Supplement and suggest to
them what to use.
5.) Discuss cal standards and best practices for each measurement by instrument type. This
information needs to be understood by instrument teams so they are consistent in design
practices.
6.) Mention SCOPE-CM and the CEOS Climate Working Group to stress the importance of
long term ECV generation. Suggest that each mission have an ECV generation plan which
would entail the development of ECVs, including data processing, data assimilation with
other instruments including calibration data, calibration standards, data storage, data
availability, and ECV data storage. Furthermore, each ECV generation plan should follow a
standard format set.
7.) Stress the importance of data access and availability. Missions/instruments must make the
mission data products publicly available for others to use in generating ECVs. Discuss how
data for ECVs may be used to generate another ECV or multiple ECVs. The data is also
important for climate models and should be made freely available to the space community.
Also discuss how analysis uncertainties and algorithms must be made available.
8.) Put out a call for the space community to work together in the generation of ECVs. Call for
international coordination of ECV data generation centers and suggest a coordinating body
organize this work (the CEOS Climate Working Group).
9.) Stress that international space agencies need to direct missions to have requirements on
instruments/missions to provide standardized data to the user community and ECV data
centers. Stress the need for a coordinating body to provide matchmaking for the
instruments/missions. Possibly call for this body to provide a mission liaison to educate
mission teams on standards, ECV data centers, etc.
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Istvan Laszlo, NOAA
Earth radiation Budget (Product A.6)
Experts at the Workshop on Continuity of Earth Radiation Budget (CERB) Observations: PostCERES Requirements held in Asheville, North Carolina, July 13-14, 2010 state that
1) To resolve changes over a decade to within current estimates of climate noise, and to be
consistent with potential climate variability a minimum stability requirement for reflected
solar radiation of 0.3 W/m2 per decade is adequate. Accuracy is not required at the same
level, and 1 W/m2 is adequate. In the longwave (LW), a minimum stability requirement
of 0.2 W/m2 is needed to resolve changes over a decade to within current estimates of
climate noise; the accuracy requirement is at the same level as the shortwave (i.e., 1
W/m2). These accuracy levels must be achieved equally under all-sky conditions as well
as for individual scenes types whose spectral content is concentrated at either end of the
Earth’s reflected solar and emitted thermal spectra (e.g., clear ocean, clear desert, deep
convective clouds, etc.).
2) Instruments for measuring broadband radiation should have onboard calibration system
as principle source of information for detecting and correcting sensor calibration drifts.
The onboard calibration system must monitor performance across the entire spectrum. To
complement the onboard calibration rigorous and robust ground characterization
procedures must be implemented.
Aerosol Properties (Product A.8)
Recent studies showed large discrepancies between the various long-term records of aerosol
optical depth (AVHRR, TOMS, MODIS, MISR). These differences must be understood and
resolved before they can be combined to give a unified aerosol record.
References:
Liu, L., and M. I. Mishchenko, 2008: Toward unified satellite climatology of aerosol properties:
Direct comparisons of advanced level 2 aerosol products, Journal of Quantitative Spectroscopy
and Radiative Transfer, Volume 109, Issue 14, September 2008, Pages 2376-2385
Li, Z., X. Zhao, R. Kahn, M. Mishchenko, L. Remer, K.-H. Lee, M.Wang, I. Laszlo, T.
Nakajima, and H. Maring, 2009: Uncertainties in satellite remote sensing of aerosols and impact
on monitoring its long-term trend: a review and perspective, Ann. Geophys., 27, 1–16.
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Claus Zehner, Bojan Bojkov, Stephen Plummer, Craig Donlon, Jerome
Benveniste, and Olivier Arino, ESA
ECV Glaciers and Ice Caps
Glaciers and glacial environments are sensitive indicators of climate change, and, in many
mountain regions, important component of the hydrological cycle.
The response time of glaciers to adjust their length to changed climatic conditions mainly
depends on their mean slope and size. Small mountain glaciers react rapidly to climatic forcing.
Typical response times of valley glaciers are 20 to 50 years. In spite of the fact that glaciers and
ice caps account only for 0.5% of the total land ice, their contribution to sea level rise during the
last century exceeded that of the ice sheets (IGOS, 2007).
Glacier changes provide some of the clearest evidence of climate change.
Glaciers and icecaps are key indicators of climate change on a global scale and rank at the same
level of confidence as direct temperature measurements (IPCC, 2007). The reasons for this
indicator function are basically two-fold:
(1)
(2)
Due to the surface temperature of glacier ice that is in most cases exactly at or only
little below 0C, any excess energy is used for melting ice. This results in a strong
correlation between annual glacier mass balance and the related climate forcing.
The dynamic and hence more long-term response of a glacier to climatic changes is
reflected in pronounced length changes. These are well visible to a large public and
make glaciers to unique demonstration objects of even small climatic changes.
Any monitoring strategy that is related to glaciers and icecaps as an ECV has to assess changes
of both glacier extent and mass. Such change assessment is not possible without a proper
reference data set that is provided by a glacier inventory (2D vector outlines) and associated
topographic surface information. Additionally, a completed detailed glacier inventory is
currently also a major demand for climate change impact assessment in hydrology at a global
(sea level rise), regional (irrigation, hydropower), and local scale (run-off, flooding, and other
natural hazards). For example, meltwater from glaciers and icecaps already is the major
contributor to global sea level rise and will continue to do so in the coming decades. However,
large uncertainties of their potential future contribution exist as the detailed global glacier
inventory is still incomplete and includes data that are of variable date. Most climate modellers
have not yet used areas covered by glaciers and icecaps in their models (e.g. as a lower boundary
condition) and still work with (static) masks for the polar icesheets only.
The aims of Global Land Ice Measurements from Space (GLIMS) Initiative are to establish a
global inventory of land ice, including surface topography (DEM), to measure the changes in the
extent of glaciers and, where possible, surface velocities. It aims also to establish a digital
baseline inventory of ice extent during the period 2000-2005 for comparison with inventories
created at earlier and later times. A large number of activities related to the satellite based
creation of glacier inventory data have started in the past decade and helped to fill the GLIMS
glacier database (GDB) at NSIDC e.g. ESA project GlobGlacier and the recently started EU FP7
project ice2sea and ESA Glacier_cci. Other major inventory efforts have been undertaken
following GLIMS guidelines for e.g. Himalaya, China and Russia.
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A comprehensive glacier observing system must be based on synergy of ground-based and
satellite-borne observing systems, complemented by airborne surveys for special studies.
Representative surveys of glaciers and ice caps will only be possible by using satellite
observations. Field measurements will also be required – for instance measurements at anchor
stations for calibrating and validating satellite-based observations and process models.
It will be essential to maintain the World Glacier Monitoring Service (WGMS) as the only
reliable (i.e. quality checked) source of standardized data on global glacier mass balance and
length changes.
1) There are large gaps in the global glacier inventory database. High-resolution
multispectral optical sensors (Landsat, SPOT, ASTER, etc.) are the most efficient means
for glacier mapping. The compilation of the first global glacier inventory is hampered by
the lack of resources for analyzing available satellite data sets, including high data costs
for some satellite data. Repeat inventories are required at 5 to 10 year intervals for global
change studies, assessing change of water resources, etc. Low cost satellite data are
required for this task.
2) Formal establishment of the responsibility of the GLIMS project is required to ensure a
fully integrated and multilevel observing strategy for glaciers within GTN-G. Regular
assessments of glacier changes (mass, length, velocity, etc.) by remote sensing techniques
should be reported in the ‘Fluctuation of Glaciers’ reports.
3) The glacier topography database is fragmentary and/or of poor quality. Space based data
are available to improve it e.g. Shuttle Radar Topography Mission (SRTM), ASTERGDEM, TerraSAR-X but they require work to ensure consistency. Improved accuracy
and spatial resolution of the future DEM observations are required for accurate estimates
of mass changes.
4) Glacier mass balance data are sparse and unsuitable either for regional and/or global
assessments or for water management. It would seem unrealistic to call for a major
increase of in situ mass balance studies. Methodologies should be further developed for
estimating mass balance from meteorological data, in synergy with remote sensing data
(topography, glacier facies, albedo, accumulation, etc.) to give a more comprehensive
picture of mass balance in various climate zones and globally.
5) Remote sensing is required for measuring snow accumulation on glaciers. Field
measurements are tedious and extremely sparse, and extrapolations from meteorological
stations and numerical weather models are flawed.
6) Comprehensive data are required on glacier velocity. Extensive global data sets on
surface velocities of glaciers were collected by the interferometric ERS tandem mission
between 1995 and 1999 and further measurements are available from ENVISAT ASAR,
RadarSat and ALOS PALSAR. However, a concerted effort is required to make these
consistent, available and accessible via GLIMS.
7) More data are required to monitor glaciers for hazards. Continuous observations are
needed from optical, medium and high spatial resolution sensors. Satellite radars enable
daily observations, but costs are high.
Based on these comments the following needs were identified by IGOS (2007):
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glacier area
glacier topography
glacier elevation change
glacier velocity
Facies and snow lines
mass balance
Accumulation
Glacier dammed lakes
Target requirements (see below)
Requirements for satellite instruments and satellite datasets) (see above)
 Open access to Landsat, SPOT, ASTER archives for key glacier regions including those
held by individual countries and industrial resellers
 Access and continuity of these acquisition systems through Sentinel, SPOT, LDCM,
CBERS et al
 Access to the key SAR archives e.g. ERS SAR, ENVISAT ASAR, RadarSat, JERS-1 and
ALOS PALSAR for topography, velocity, Glacial lakes and mass balance determination
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Calibration, validation and data archiving needs
 Adherence to standards and guidelines established under GLIMS/GlobGlacier/WGMS
 Concerted efforts to acquire high resolution optical data for sample site validation of
observations at Landsat scale.
 Continuity of existing archives (in situ obs and satellite - GLIMS) needs to be assured.
Adequacy/Inadequacy
 The GLIMS inventory is incomplete and requires urgent completion and updating where
necessary
 New inventories at country/regional level need to be interfaced with GLIMS (Himalaya,
FSU, China)
 The WGMS is now maintained in the long term via GCOS Switzerland but some of the
glaciers used for monitoring are in danger of collapse - new glaciers for monitoring need
to be added and the geographical representativeness improved.
Immediate Action
 Make data held in country level archives of Landsat available for key regions of interest
 Ensure long term future for GLIMS
 Improve coverage from different sensor systems (optical and radar) and comparability of
methods.
 Increase the archive richness by adding topography, velocity and mass balance
Ozone ECV:
Activities will concentrate on three types of Ozone data products:
-
Total ozone: The L2 retrieval algorithm baseline is the GOME DATA PROCESSOR
(GDP) 5, which will also be applied to SCIAMACHY and GOME-2 data. OMI data will
be included in the merged data set (using the NASA OMTO3product). This data set will
cover the period 1995 until now.
-
Low resolution ozone profiles from nadir sounders: A Round-Robin exercise will be
performed to select/combine the best of the two existing KNMI (OPERA-OMI) and the
RAL retrieval algorithms. The GOME, SCIAMACHY, GOME-2, and OMI sensors will
be included in the prototype ECV parameter generation. The first prototype data set will
consist of a minimum of two contiguous years.
-
Higher resolution ozone concentration profiles derived in the upper troposphere and in
the stratosphere using limb and occultation types of instruments: The limb profile data
product will be generated by merging data from three different sensors: MIPAS,
GOMOS, and SCIAMACHY. For GOMOS, this will rely on the ESA operational data
product. For SCIAMACHY it will be based an advanced (IUP) scientific product which
provides a better altitude coverage than the operational product. For MIPAS several
competing algorithms will be inter-compared. Detailed error characterization will be
performed for all three sensors. The Envisat data will be extended by TPM missions
(Odin, ACE). The first prototype data set will cover at least two contiguous years.
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GHG ECV:
Activities will concentrate on 2 types of GHG data products:
Two existing satellite sensors will be used as the main data sources:
SCIAMACHY on ENVISAT and TANSO on GOSAT. Both instruments measure NIR/SWIR
spectra of reflected solar radiation and are sensitive to CO2 and CH4 concentration changes
close to the Earth’s surface.
A two-year, round-robin exercise will be conducted for ten different CO2 and CH4 retrieval
algorithms, as developed by IUP, SRON, and ULE for SCIAMACHY and GOSAT. GHG data
products (columns and profiles) derived from AIRS, IASI, MIPAS and ACE-FTS measurements
will also be used in scientific studies to assess the extent to which they can constrain surface
fluxes.
The best algorithms will be applied to the most complete satellite observations record available.
A fast processing scheme, combining SCIAMACHY and GOSAT measurements, will be used to
cover the time period 2002 until present. This can potentially deliver a consistent ten-year record
of total columns for both species. A more accurate, but highly computationally intensive, ‘full
physics’ processing scheme will also be applied to a single year of data.
For both ECVs the CEOS ACC (Atmospheric Composition Constellation) will investigate the
possibility during the next year to have dedicated ACC projects to combine these 'European' data
sets with others (e.g. as produced by NOAA, NASA, JAXA).
CLOUD ECV:
After some iterations with cloud data users (and confirmed by modelers at the GEWEX cloud
assessment meeting in Berlin), the following is suggested for all cloud parameters:
-
10*10 km2 resolution instead of 100*100km2
with a 6h reporting (0, 6, 12, 18) instead of 3h reporting
the accuracy issue is still to be determined... hopefully within cloud
cci
ECV Land Cover
Accuracy of 15% is impressive, specifically for some class.
A solution would be to pile up 5 consecutive years at medium resolution to approach this
accuracy.
The accuracy is also dependent on how many classes are needed (what is the requested number
of classes?)
GlobCover2005 is available publicly since end 2008 300 meter resolution with a weighted
accuracy of 75 % with 22 classes on ESA server www.esa.int/due/ionia/GlobCover
GlobCover2009 is under validation and is about to be released at the same address.
Is the LCCS appropriate for climate modellers?
For the high resolution Land Cover the two Sentinel-2 that launch is planned for 2013 and 2014
at 10 meter resolution with 290 km swath systematically acquired and processed in less than 100
minutes to orthorectified products should be considered as the workhorse for such doing.
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3.2.2. ECV Sea Level
Sea-level rise, including the changing frequency and intensity of extreme events, is one of the main
impacts of anthropogenic climate change, and is particularly important to all low-lying land
regions, including many small-island states. Changes in sea level are a significant parameter in the
detection of climate change and an indicator of our ability to model the climate system adequately.
Sea level is also an indicator of ocean circulation and is an important component in initializing
ocean models for seasonalto-interannual and possibly decadal climate prediction.
The following is required for this ECV:
Product O.2 Sea level and variability of its global mean
Benefits
• Estimates of state of the global ocean
• Evaluation of skill of climate change projections
• Critical information to coastal communities
Target requirements
• Accuracy: 1 cm
• Spatial and temporal resolution: 25 km horizontal resolution, daily observing cycle
• Stability: 0.5 mm/decade
Requirements for satellite instruments and satellite datasets
FCDR of appropriate satellite altimetry, for example through:
• One high-precision altimeter operating at all times, with planned extensive overlaps between
successive missions, and two lower-precision but high-resolution altimeters to provide
needed sampling. (GIP Action O12)
• Precision altimetry, started by TOPEX (launched August 1992, ended October 2005) and
continued by Jason (launched December 2001, currently in service), and then to be followed
by the Ocean Surface Topography Mission (Jason-2, launch mid-2008); requires urgently the
establishment of an ongoing series of follow-on missions in the same orbit
• Planning for launch of high-inclination, long repeat cycle altimetry missions for necessary
coverage and real-time applications, such as Envisat or the Geosat follow-on missions, with a
relax on the high-precision requirement thanks to the use of high-precision missions as
reference.
Calibration, validation and data archiving needs
• Jason and Envisat-class mission continuity is necessary
• Ancillary systems, such as tide gauges, calibration sites, precision orbit determination, path
length corrections, including best estimates of the marine geoid, must also be considered part
of these missions
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•
Complete reprocessing of altimetry data on a regular basis is a necessary climate system
function because continuous improvement in orbit determination and tidal models provide
improvements to the entire data record length
Adequacy/inadequacy of current holdings
Satellite altimetry, supplemented with tide gauges, has proved adequate to revolutionize the view
of global sea-level variability. Current analysis efforts should be maintained and strengthened.
Immediate action, partnerships and international coordination
Continue the precision altimetry satellite time series through 2020. This is an opportunity to
provide the data to unambiguously determine if global sea-level rise is accelerating. The present
>13-year satellite data record, when compared with 20th century tide-gauge data and ice/land data
records, suggest that the rate of sea-level rise may have doubled in the most recent decade.
Link to GCOS Implementation Plan
[GIP Action O12] Ensure continuous coverage from one high-precision altimeter and two lowerprecision but higher-resolution altimeters.
Other applications
• Ocean surface topography data provide the core data that enable ocean state estimates from
global ocean data assimilation activities
• Critical information to coastal communities
3.2.3. ECV Sea Surface Temperature
Together with air temperature over land, sea-surface temperature (SST) is a fundamental
indicator of the state of the climate system on all time scales. It is also critical for weather
forecasting under certain conditions. In warm-water regions (T>26°C), SST appears to be a
strong and sensitive factor for the formation of tropical cyclones, and (T>28°C) for coral-reef
bleaching. SST is also important for operational oceanography, for the estimation of net air-sea
flux of carbon, and many other marine applications. There are three distinct sea-‘surface’
temperatures in common use: the traditional in situ SST at a stated depth (SSTdepth) measured
by in situ infrastructure, the ‘sub-skin’ SST assumed to be measured by a passive microwave
rasdiometer and ‘skin’ SST measured by an infrared radiometer. Long-term historical climate
data sets of “SST” have been traditionally based upon a blend of in situ SST data at varied depths
and IR ‘skin’ SST measurements. Climate-quality blended analyses that make use of in situ, IR
and microwave observations are required to meet GCOS SST requirements.
The following is required for this ECV:
Product O.3 Sea-surface temperature
Benefits
• Fundamental indicator for the state of the climate system
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• Input parameter for seasonal-to-interannual climate forecasting
Target requirements
Known patterns of interannual and longer-term climate variability have amplitudes of several
degrees C over basin scales. Mesoscale variability has scales of 10-50 km with similar
amplitudes over several days. Coastal variability has comparable or larger amplitudes and occurs
on scales as small as 1 km over several hours. The diurnal cycle can be 4-6 C magnitude in
certain regional-local low–wind conditions and can be aliased into lower frequencies if not
sampled properly. Global-average warming trends are estimated to be about 0.5°C over 100
years.
• Accuracy: 0.25°C
• Spatial and temporal resolution: 1 km horizontal resolution, 3-hourly measurement cycle in
coastal regions and to resolve diurnal variability.
• Stability: 0.05°C
Requirements for satellite instruments and satellite datasets
FCDRs of appropriate IR and microwave measurements are required.


Sustained IR and microwave sensors, capable of supporting climate accuracy global SST
analyses and adhering to GCOS satellite Climate Monitoring Principles.
Stable well calibrated high-accuracy and high temporal stability SST measurements are
required from AATSR-class instruments that can be used to monitor variability and tie
together wider SST coverage measurements from low Earth orbit and geostationary
instruments in the IR and microwave, to provide for an all-weather diurnal and high
spatial resolution capability.
Calibration, validation and data archiving needs




Work needs to continue on the use of in situ observations for product calibration and
validation and for cloud and aerosol characterization. Comparison of products from
independent measurements and analyses remains a priority.
Expand in situ network of appropriate shipborne surface-viewing radiometers for
calibration and validation of satellite SST data sets.
Shipborne radiometers must be maintained as a reference data set for inter-calibration of
follow-on satellite missions. This is particularly important where gaps in data exist
between follow on missions.
Validation of SST measurements from satellite must be performed over the entire satellite
mission duration with appropriate planning and coordination.
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Adequacy/inadequacy of current holdings



There are opportunities for additional reprocessing of infrared satellite data – particularly
geostationary data.
Significant effort is required to develop better passive microwave SST retrievals.
In situ SST measurments must include metadata describing calibration details and the
deopth at which the measurement is taken.
Immediate action, partnerships and international coordination









Immediate action is required to sustain satellite passive microwave “all weather” SST
measurement capability
Immediate action is needed to sustain the quality of the satellite-era SST data record.
Sustain the in situ observing system described in the GIP, namely sustain the global array
of surface drifting buoys, Volunteer Observing Ships (and the VOSClim subset of them)
and time series mooring sites (tropical moored arrays and OceanSites reference array)
Sustain and augment the ARGO profiling drifter network with better capability to resolve
diurnal thermal stratification in the surface ocean. Argo profiling floats should be
equipped with a capability to make detailed SST vertical profile measurments in the 10 m
of the ocean.
Better cloud screening algorithms are required for infrared measurement data sets
Better calibration and treatment of side-lobe contamination is required for passive
microwave measurements
Continue reprocessing of satellite data for providing a homogeneous global SST climate
data record, in particular from AVHRR and the (A)ATSR series, from 1991 to 2010
Maintain both the high frequency observations sufficient to resolve diurnal variability,
provided at present by geostationary instruments, together with more limited coverage
AATSR-class capability
Support national participation in GCOS SST/Sea Ice Working Group and SST activities
recommended by WOAP
Link to GCOS Implementation Plan
[GIP Action O9] Ensure a continuous mix of polar orbiting and geostationary IR measurements
combined with passive microwave coverage. To link with the comprehensive in situ networks
noted in O10.
[GIP Action O10] Obtain global coverage, via an enhanced drifting buoy array (total array of
1250 drifting buoys equipped with atmospheric pressure sensors as well as ocean temperature
sensors), a complete Tropical Moored Buoy network (~120 moorings) and the improved
VOSClim ship fleet.
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Other applications
Operational oceanography, weather forecasting (including tropical cyclones), fisheries
management, human health, transport of invasive species, ecosystem dynamics, recreational
opportunities, hazardous material spill impacts, the net air-sea flux of carbon, and other marine
applications.
Jörg Schulz, EUMETSAT
1)
GCOS-107 has to be rewritten reflecting the new/updated GCOS-138. This means in
particular that new coordination mechanisms already existing, e.g., GSICS and SCOPECM or upcoming as the CEOS CWG need to be mentioned in the updated GCOS-107.
2)
Within the section 1.5 on scientific coordination the new structure of WCRP should be
reflected. This includes coordination activities in the frameworks of research to
operations as well as research and operations. For data set production research to
operations means that the research and operational communities are working towards a
hand over of production schemes to operational environments. At the same time there is a
need for a mechanism on how research can influence the further development. This we
might call research and operations. One particular point in this is the periodically
assessment of existing and new products that can be led by science. Important is also that
assessments need resources to be successful.
3)
GCOS 107 and also the new GCOS-138 use the term "ECV product" with the reference
that other documents use the term "Thematic Climate Data Record". I am sure that this
issue was certainly discussed at some point but I like to mention that in the recent past
the name "ECV product" has caused some discussions within organisations as many
people believe if we just deliver such geophysical variables we are able to do ECV
products. Sometimes such discussions are decoupled from the GCOS documents which
of course explain what is meant. In my personal opinion the name just misses the notion
of "climate" to make clear that we look for high quality only, i.e., a combination of ECV
and CDR would be most appropriate.
4)
Sections on instrument calibration (C.1) need revision with to better reflect the role of
GSICS as it has evolved somewhat. Also in this section efforts to establish observations
that are directly traceable to SI standard on orbit, such as CLARREO and TRUTHS
should be mentioned.
5)
In section C.4 there should be remarks on the SCOPE-CM initiative that has started to
work on the C.4 actions.
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6)
When describing individual ECVs there should be more emphasis on the fact that data
records should have uncertainty estimates. For some ECVs it is mentioned but it should
be mentioned in almost all ECV sections and some actions might be created in areas
where those do not exist.
7)
For the temperature ECV in the adequacy section it should be reflected that differences
between temperature time series from MSU data have now been substantially reduced
since 2006.
8)
For the water vapour ECV a bit of a review on what instrument can do what should be
done. Also a structure into total column content, profiles and upper tropospheric and
stratospheric humidity could be helpful to improve the clarity of the section.
9)
For the ECVs precipitation, cloud properties and aerosols the updated GCOS-107 should
reflect results from the data set assessments performed by the GEWEX Radiation Panel.
There might be other assessments for some ECVs.
10) Atmospheric and ocean reanalysis may not be treated as ECVs (as 3.1.11) but rather as
tools to consistently combine different FCDRs.
11) An updated version with mark up changes should be subject to open review.
John L. Dwyer, USGS
Initial comments:
1.3 Improved knowledge of climate change underpins many other “societal benefit areas” (as
defined by the GEOSS 10-year implementation plan11), such as Weather, Water, Agriculture,
Health and Energy. Such as Weather, Water, Agriculture, Health and Energy. Why limit these,
and include: Disasters, Ecosystems, Biodiversity
2.0 C.1 c. The Global Space-based Inter-Calibration System (GSICS), currently under
development operating via CGMS and WMO, is a good example of a proposal expressing the
needs for instrument calibration, and may be considered for wide adoption by space agencies.
The GSICS proposal contains recommendations for:
 Ensuring traceable pre-launch and on-board calibration;
 Exploiting opportunities for calibration against external targets, e.g., Earth-based
reference sites and the Moon;
 Exploiting opportunities for instrument cross-calibration, e.g., by maintaining a database
of common satellite viewpoints, including designated radiosonde and surface-based
measurement sites, and airborne measurements. The GSICS proposal is consistent and in
compliance with the GEO and CEOS QA4EO recommendations.
2.0 C.1.d
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
The provision of a set of key terrestrial reference sites, providing measurements of key
biomes according to agreed standards. An example would be the MODIS Land Product
Validation sites.
2.0 C 2
Remarks: Add
Established metadata standards should be employed to ensure interoperability of data and
product inventories.
2.0 C4.5 b. Whenever possible, the required data records for the generation of products,
including historical data records, should cover as many years as possible (at least a minimum the
most recent 30 years, if possible) in order to serve as a reference for climate variability and
change studies;
2.0 C 4
Remarks: Add
e. In many climate applications, the FCDRs themselves, mostly calibrated radiances, are the
critical and required observables. This necessitates open access to those FCDRs, including their
comprehensive metadata that contains information on the uncertainties of the measurement or
derived parameter.
2.0 C 7: Add
Exploit the unique value of historical datasets through reprocessing to derive multi-decadal
products, for example land cover, fire disturbance and aerosols from AVHRR and Landsat data.
3.1.4 Cloud ice profile (total column):
Accuracy: - missing
Spatial and temporal resolution: 100 km horizontal resolution, 3-hourly observing cycle
Cloud water profile (total column):
Accuracy: - missing
Spatial and temporal resolution: 100 km horizontal resolution, 3-hourly observing cycle
3.1.8 Calibration, validation and data archiving needs
Satellite measurements of back-scattered solar radiation require very accurate calibration.
Comprehensive ground-based independent validation measurements are required. These can be
provided by existing networks or extensions of the NDACC and GAW networks, the NASA
AERONET observations and other lidar networks, with quality assurance coordinated by WMO
GAW.
Does this include SURFRAD and CRN?
3.3.2
Requirements for satellite instruments and satellite datasets: Add
FCDR of appropriate VIS/NIR/SWIR multispectral imagery, for example through:
 Historical archived Landsat-4/5 Thematic Mapper and Landsat 7 enhanced thematic
mapper plus data.
Page 44
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Calibration, validation and data archiving needs
Global archives held by USGS/DAAC/ESA
Does the DAAC= NASA?
Adequacy/inadequacy of current holding: Add
“…robust semi-automatic methods for delineation of debris-free glaciers from multispectral
Landsat
Thematic Mapper (TM), enhanced thematic mapper plus (ETM+), and ASTER data…”
Delete: Archived Landsat 4/5 Thematic Mapper data exist, but appropriate arrangements for
data discovery and access should be made (marginal cost of reproduction); the Global Land
Cover Facility (GLCF) offer scenes for free. (Landsat data are now offered at no cost.)
Add: Landsat 7 lost its scan line corrector in 2003, which reduced the quality of single images at
the outer edges of the swath; Landsat 5 has been in operation since 1984 and might fail soon;
ASTER is already beyond its expected lifetime. An operational Landsat class system is required.
Immediate action, partnerships and international coordination: Add
The generation of a consistent historical Landsat data record spanning and including Landsat 4/5
TM and Landsat 7 ETM+ data record would provide major advancement in global monitoring of
glaciers
Page 49 - Historical land-cover datasets could should be generated on a decadal scale from the
1970s to 2000 --- and continually Landsat type data collection should be continued to support
these datasets.
Page 52
Adequacy/inadequacy of current holdings: Add
 The Global Land Survey 1990, 2000, 2005, and 2010 Landsat data sets provide consistent
baseline data by which to derive high resolution land cover data. The GLS1990 would be
roughly contemporaneous with the IGBP DISCover data, and similarly the GLS2000
with the GLOBCOVER product.
Page 53
Other Applications: Add
 Land surface temperature is an important parameter for evopotranspiration models,
particularly in support of water use consumption for irrigated agriculture
Page 54
Requirements for satellite instruments and satellite datasets
Need to add a statement on the temporal frequency that is required, e.g. daily observing cycle
that would be consistent with LAI.
Page 55
Benefits: Add
 Important parameter for models of ecosystem function and carbon sequestration
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This should be reviewed for accuracy: GCOS requirements in WMO/CEOS Database (13
July 2004)
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