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Nov. 3, 2008
Jan. 10, 2003 - local noon, Kiruna, Sweden
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Jan. 14, 2003 Southern Norway
Nov. 3, 2008
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Polar Stratospheric Ozone
Dr. Paul A. Newman
http://code613-3.gsfc.nasa.gov/People/Newman/
NASA’s Goddard Space Flight Center
IPY Webcast
NASA GSFC
Nov. 3, 2008
Nov. 3, 2008
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Ozone Basic Facts
O3 = Ozone is composed of 3 oxygen atoms.
Ozone
O3 concentrations are small (peak concentrations are
about 10 parts per million at an altitude of about 32
km (20 miles).
O3 absorbs harmful solar ultraviolet radiation. A
necessary condition for life.
O3 is mainly found in the the stratosphere.
Oxygen
O3 at the ground is a problem! Inhalation of ozone for
very small concentrations can cause lung problems .
Mass: (Billion Metric Tons)
Sun
1,9900,000,000,000,000,000
Earth
5,980,000,000,000
Global atmosphere
5,300,000
Global ozone
3
Nov. 3, 2008
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Atmospheric Composition
•
•
•
•
Nitrogen
Oxygen
Argon
Water
• CO2
• O3
Nov. 3, 2008
78.1%
20.9%
0.9%
1.4% (tropics)
0.2% (poles)
0.0004% (stratosphere)
0.0360%
0.001% (stratosphere)
0.00001% (troposphere)
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Atmospheric Structure
-135oF
-99oF
-63oF
-27oF
9 oF
45oF
81oF
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
Stratosphere 20
20
10
Troposphere
0
180
200
220
240
260
Temperature (K)
Nov. 3, 2008
280
0
300
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Atmospheric Structure
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
Stratosphere
20
20 Airliners fly at 30,000-40,000 feet
10
Troposphere
0
Nov. 3, 2008
0
8
Atmospheric Structure
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
ER-2 flies at 70,000 feet
Stratosphere
20
20
10
Troposphere
0
Nov. 3, 2008
0
9
Atmospheric Structure
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
Oxygen
Ozone
Stratosphere
20
20
10
Troposphere
0
Nov. 3, 2008
0
10
Ozone Facts
QuickTi me™ a nd a
TIFF (Uncompre ssed ) decomp resso r
are need ed to se e th is p icture.
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
90% of ozone is in the
stratosphere
20
20
10
Troposphere
0
0
2
4
6
Ozone (parts per million)
Nov. 3, 2008
8
0
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Ozone Facts
100
60
Thermosphere
Altitude (km)
50
Mesosphere
Altitude (miles)
80
40
60
30
40
Stratosphere
20
20
10
10% of ozone is in the troposphere
0
0
2
4
6
Ozone (parts per million)
Nov. 3, 2008
8
0
12
Digression: Dobson Units
• Total Ozone is a measure of the
total column amount above us.
Measured in Dobson Units
• If we bring all of the ozone above
us down to the Earth’s surface
• The thickness would be about 3
millimeters (~0.1 inches) = 300
Dobson Units (approximately the
global average)
• 100 Dobson Units = 1 millimeter in
thickness
2¢
10¢
3 mm = 300 Dobson Units
Nov. 3, 2008
 The Dobson Unit is a convenient unit of
measurement for total column ozone
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Ozone Facts
Ozone is the Earth’s natural sunscreen
60
80
UVc - 100% Absorption
UVb - 90% Absorption
UVa - 50% Absorption & Scattering
60
50
Altitude (miles)
Altitude (km)
100
40
30
40
Stratosphere
20
20
10
0
0
2
4
6
Ozone (part per million)
Nov. 3, 2008
8
0
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UV Health Facts
• UV pluses: produces vitamin D in the skin necessary to maintain levels of calcium and
phosphorus (10-15 minutes twice a week)
• UV minuses:
– Eye damage: cataracts, photokerititus
(snowblinding), ocular cancers
– Skin cancers: basal, squamous,
melanoma
– photoaging
– Damage to various land speciesDamage
to aquatic species
– Increased pollution levels in urban
environments
Nov. 3, 2008
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Cataract
Melanoma
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Mexico City
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Large polar ozone losses
result from chlorine and
bromine compounds that are
mainly human produced
Nov. 3, 2008
Chlorine Pathway
Cl catalytically destroys O3
Cl reacts with CH4 or
CFC-12 photolyzed in
NO2 to form nonstratosphere by solar UV,
reactive HCl or
releasing Cl
ClONO2
Polar
loss
Carried into stratosphere in
the tropics by slow rising
circulation
CFC-12 released in troposphere
Nov. 3, 2008
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Source Gases
1%
4%
5%
7%
3400
3000
Other gases
Methyl chlor oform (CH3CCl3)
HCFCs (e.g., HCFC-22 = CHClF2)
CFC-113 (CCl2FCClF2)
Other halons
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Carbon tetrachloride
(CCl4)
12%
14%
Halon-1301 (CBrF 3)
Halon-1211 (CBrCIF 2)
15
CFC-11 (CCl3F)
20%
5-20%
2000
23%
4%
Methyl bromide (CH 3Br)
10
CFC-12 (CCl2F2)
1000
5
32%
0
Natural
sources
16%
27-42%
Methyl chloride (CH3Cl)
0
Very-short lived gases
(e.g., bromoform = CHBr 3)
15%
• Cl is much more abundant than Br, but …
• Br is about 60 times more effective at O3 destruction
Nov. 3, 2008
From Ozone FAQ - see http://www.unep.org/ozone/faq.shtml
Atmospheric Chlorine Trends from
NOAA/ERL - Climate Monitoring Division
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102 years
CFC-12
CFC-11
CCl4
CFC-113
CH3CCl3
Nov. 3,
50 years
42 years
85 years
5 years
Updated Figure made by Dr. James Elkins from Trends of the Commonly Used Halons Below Published by Butler et al. [1998],
2008All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).
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Polar Stratospheric Clouds
Central, Sweden January 14, 2003 - P. Newman
Nov. 3, 2008
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Antarctic ozone hole theory
Solomon et al. (1986), Wofsy and McElroy (1986),
and Crutzen and Arnold (1986) suggest reactions
on cloud particle surfaces as mechanism for
activating Chlorine
HCl
Cl2
ClONO2
Nov. 3, 2008
HNO3
Cl2 is easily photolyzed by UV & blue/green light
HNO3 is sequestered on PSC
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Polar Ozone Destruction
1. O3 + Cl  ClO + O2
3. ClOOCl+h2 Cl+O2
2 O3
3 O2
2. 2 ClO + M  ClOOCl + M
Only visible light (blue/green) needed for photolyzing ClOOCl
No oxygen atoms required
Nov. 3, 2008
Net: 2O3 + h  3O2
Antarctic Measurements
Nov. 3, 2008
Aurora over Halley Bay Station, Antarctica, 75.6ºS 26.5ºE
Brunt Ice Shelf, Coats Land
105 days of continuous darkness, twice per year re-supply
Population: 65 in summer, 15 in winter
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October Antarctic Ozone pre-1985
Nov. 3, 2008
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October Antarctic Ozone
Nov. 3, 2008
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TOMS - August 31, 2003
Orange/Yellow indicates
higher ozone levels.
Dark color over pole shows
the extent of polar night, no
ozone observations
Nov. 3, 2008
Antarctic ozone hole
is defined as the
region covered by
low ozone values
Blue colors indicate
low ozone values
Ozone Hole Area
Sep. 21, 2008
N. America
Sep. 30, 2008
1st observed SH major warming (2002)
10/25/2008
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October Average Ozone Hole
Nov. 3, 2008
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March Average total ozone
Nov. 3, 2008
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Arctic & Antarctic Trends
Nov. 3, 2008
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What’s being done?
Nov. 3, 2008
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What Can You Do?
• Avoid excessive solar exposure (limit sun between
11AM and 2PM).
• Wear and encourage others to wear sunscreen (SPF
rating of 15). Even with sunscreen, prolonged
exposure is not smart.
• Check your skin regularly.
• Wear sunglasses that screen UV.
• Hats and other coverings
• Make note of the UV index on the news or web:
http://www.epa.gov/sunwise/uvindex.html
Nov. 3, 2008
Atmospheric Chlorine Trends from
NOAA/ERL - Climate Monitoring Division
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102 years
CFC-12
CFC-11
50 years
U. S. CFC production stopped by
President George Bush in 1992
CCl4
Montreal Protocol Signed (1987)
CFC-113
CH3CCl3
Nov. 3,
42 years
85 years
5 years
Updated Figure made by Dr. James Elkins from Trends of the Commonly Used Halons Below Published by Butler et al. [1998],
2008All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).
Antarctic EESC
Obs. Projections
Using WMO scenario A1-adj., we can project forward
from 1980 to show recovery of EESC around 2065.
Recovery of 1970 Antarctic EESC in 22nd century!
10/25/2008
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Ozone future
Projected area
of the ozone
hole
Nov. 3, 2008
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Summary
• Stratospheric ozone is a critical gas for
screening solar UV radiation.
• Human produced ozone destroying
substances (ODS) have caused large losses
of polar ozone over both poles
• ODSs have been regulated under
international agreements and are slowly
decreasing. Ozone levels should recover
within the next 50-70 years.
• Climate change remains a big unknown for
ozone recovery
Nov. 3, 2008