Nov. 3, Jan. 10, local noon, Kiruna, Sweden

Nov. 3, Jan. 14, 2003 Southern Norway

Nov. 3, Polar Stratospheric Ozone Dr. Paul A. Newman NASA’s Goddard Space Flight Center IPY Webcast NASA GSFC Nov. 3, 2008 Dr. Paul A. Newman NASA’s Goddard Space Flight Center IPY Webcast NASA GSFC Nov. 3, 2008

4 Ozone Basic Facts O 3 = Ozone is composed of 3 oxygen atoms. O 3 concentrations are small (peak concentrations are about 10 parts per million at an altitude of about 32 km (20 miles). O 3 absorbs harmful solar ultraviolet radiation. A necessary condition for life. O 3 is mainly found in the the stratosphere. O 3 at the ground is a problem! Inhalation of ozone for very small concentrations can cause lung problems. Mass: (Billion Metric Tons) Sun1,9900,000,000,000,000,000 Earth5,980,000,000,000 Global atmosphere5,300,000 Global ozone3 Oxygen Ozone

Nov. 3, Atmospheric Composition Nitrogen78.1% Oxygen20.9% Argon0.9% Water1.4% (tropics) 0.2% (poles) % (stratosphere) CO % O % (stratosphere) % (troposphere) Nitrogen78.1% Oxygen20.9% Argon0.9% Water1.4% (tropics) 0.2% (poles) % (stratosphere) CO % O % (stratosphere) % (troposphere)

Nov. 3, Temperature (K) Altitude (km) Troposphere Stratosphere Mesosphere Thermosphere Atmospheric Structure Altitude (miles) o F45 o F9oF9oF-27 o F-63 o F-99 o F-135 o F

Nov. 3, Altitude (km) Troposphere Stratosphere Mesosphere Thermosphere Atmospheric Structure Altitude (miles) Airliners fly at 30,000-40,000 feet

Nov. 3, Altitude (km) Troposphere Stratosphere Mesosphere Thermosphere Atmospheric Structure Altitude (miles) ER-2 flies at 70,000 feet

Nov. 3, Altitude (km) Troposphere Stratosphere Mesosphere Thermosphere Atmospheric Structure Altitude (miles) Oxygen Ozone

Nov. 3, Ozone (parts per million) Altitude (km) Troposphere Mesosphere Thermosphere Ozone Facts Altitude (miles) % of ozone is in the stratosphere 02468

Nov. 3, Ozone (parts per million) Altitude (km) Stratosphere Mesosphere Thermosphere Ozone Facts Altitude (miles) % of ozone is in the troposphere

Nov. 3, Digression: Dobson Units 3 mm = 300 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 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 *The Dobson Unit is a convenient unit of measurement for total column ozone 2¢ 10¢

Nov. 3, Ozone (part per million) Altitude (km) Stratosphere Ozone Facts Altitude (miles) UVc - 100% Absorption UVb - 90% Absorption UVa - 50% Absorption & Scattering Ozone is the Earth’s natural sunscreen

Nov. 3, 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 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 Cataract Melanoma Mexico City

Nov. 3, Large polar ozone losses result from chlorine and bromine compounds that are mainly human produced

Nov. 3, CFC-12 released in troposphere Carried into stratosphere in the tropics by slow rising circulation CFC-12 photolyzed in stratosphere by solar UV, releasing Cl Cl catalytically destroys O 3 Cl reacts with CH 4 or NO 2 to form non- reactive HCl or ClONO 2 Polar loss Chlorine Pathway

Nov. 3, Source Gases Cl is much more abundant than Br, but … Br is about 60 times more effective at O 3 destruction From Ozone FAQ - see

Nov. 3, Atmospheric Chlorine Trends from NOAA/ERL - Climate Monitoring Division Updated Figure made by Dr. James Elkins from Trends of the Commonly Used Halons Below Published by Butler et al. [1998], All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC). 50 years 102 years 5 years 42 years 85 years CFC-11 CCl 4 CFC-113 CFC-12 CH 3 CCl 3

Nov. 3, Polar Stratospheric Clouds Central, Sweden January 14, P. Newman

Nov. 3, 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 ClONO 2 HNO 3 Cl 2 Cl 2 is easily photolyzed by UV & blue/green light HNO 3 is sequestered on PSC Antarctic ozone hole theory

Nov. 3, Polar Ozone Destruction 1. O 3 + Cl  ClO + O 2 Only visible light (blue/green) needed for photolyzing ClOOCl No oxygen atoms required Net: 2  O 3 + h  3  O 2 2 O 3 3 O 2 3. ClOOCl+h  2 Cl+O ClO + M  ClOOCl + M

Nov. 3, Antarctic Measurements 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 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

Nov. 3, October Antarctic Ozone pre-1985

Nov. 3, October Antarctic Ozone

Nov. 3, TOMS - August 31, 2003 Orange/Yellow indicates higher ozone levels. Blue colors indicate low ozone values Dark color over pole shows the extent of polar night, no ozone observations Antarctic ozone hole is defined as the region covered by low ozone values

10/25/ Ozone Hole Area N. America 1 st observed SH major warming (2002) Sep. 21, 2008 Sep. 30, 2008

Nov. 3, October Average Ozone Hole

Nov. 3, March Average total ozone

Nov. 3, Arctic & Antarctic Trends

Nov. 3, What’s being done?

Nov. 3, 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: 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:

Nov. 3, Atmospheric Chlorine Trends from NOAA/ERL - Climate Monitoring Division Updated Figure made by Dr. James Elkins from Trends of the Commonly Used Halons Below Published by Butler et al. [1998], All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC). 50 years 102 years 5 years 42 years 85 years CFC-11 CCl 4 CFC-113 CFC-12 CH 3 CCl 3 U. S. CFC production stopped by President George Bush in 1992 Montreal Protocol Signed (1987)

10/25/ Antarctic EESC Obs.Projections Using WMO scenario A1-adj., we can project forward from 1980 to show recovery of EESC around Recovery of 1970 Antarctic EESC in 22 nd century!

Nov. 3, Ozone future Projected area of the ozone hole

Nov. 3, 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 years. Climate change remains a big unknown for ozone recovery 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 years. Climate change remains a big unknown for ozone recovery