极地上空臭氧空洞-保护环境!

1、Nov. 3, 20081Jan. 10, 2003 - local noon, Kiruna, SwedenNov. 3, 20082Jan. 14, 2003 Southern NorwayNov. 3, 20083Polar Stratospheric OzoneDr. Paul A. Newman/People/Newman/NASAs Goddard Space Flight CenterIPY WebcastNASA GSFCNov. 3, 2008Nov. 3, 20084Ozone Basic FactsO3 = Ozo

2、ne is composed of 3 oxygen atoms.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.O3 at the ground is a pr

3、oblem! Inhalation of ozone for very small concentrations can cause lung problems .Mass: (Billion Metric Tons)Sun1,9900,000,000,000,000,000Earth5,980,000,000,000Global atmosphere5,300,000Global ozone3OxygenOzoneNov. 3, 20085Atmospheric Composition Nitrogen78.1% Oxygen20.9% Argon0.9% Water1.4% (tropic

4、s) 0.2% (poles) 0.0004% (stratosphere) CO20.0360% O30.001% (stratosphere) 0.00001% (troposphere)Nov. 3, 20086180200220240260280300Temperature (K)020406080100Altitude (km)TroposphereStratosphereMesosphereThermosphereAtmospheric StructureAltitude (miles)100203040506081oF45oF9oF-27oF-63oF-99oF-135oFNov

5、. 3, 20087020406080100Altitude (km)TroposphereStratosphereMesosphereThermosphereAtmospheric StructureAltitude (miles)1002030405060Airliners fly at 30,000-40,000 feetNov. 3, 20088020406080100Altitude (km)TroposphereStratosphereMesosphereThermosphereAtmospheric StructureAltitude (miles)1002030405060ER

6、-2 flies at 70,000 feetNov. 3, 20089020406080100Altitude (km)TroposphereStratosphereMesosphereThermosphereAtmospheric StructureAltitude (miles)1002030405060OxygenOzoneNov. 3, 200810QuickTime and aTIFF (Uncompressed) decompressorare needed to see this picture.Ozone (parts per million)020406080100Alti

7、tude (km)TroposphereMesosphereThermosphereOzone FactsAltitude (miles)100203040506090% of ozone is in the stratosphere02468Nov. 3, 200811Ozone (parts per million)020406080100Altitude (km)StratosphereMesosphereThermosphereOzone FactsAltitude (miles)10020304050600246810% of ozone is in the troposphereN

8、ov. 3, 200812Digression: Dobson Units3 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 Earths surface The thickness would be about 3 millimeters (0.1 inches) = 300 Dobson Units (approximate

9、ly the global average) 100 Dobson Units = 1 millimeter in thickness* The Dobson Unit is a convenient unit of measurement for total column ozone210Nov. 3, 200813Ozone (part per million)020406080100Altitude (km)StratosphereOzone FactsAltitude (miles)100203040506002468UVc - 100% AbsorptionUVb - 90% Abs

10、orptionUVa - 50% Absorption & ScatteringOzone is the Earths natural sunscreenNov. 3, 200814UV 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 (snowblindi

11、ng), ocular cancers Skin cancers: basal, squamous, melanoma photoaging Damage to various land speciesDamage to aquatic species Increased pollution levels in urban environmentsQuickTime and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime and aTIFF (Uncompressed) decompressor

12、are needed to see this picture.CataractMelanomaMexico CityNov. 3, 200815Large polar ozone losses result from chlorine and bromine compounds that are mainly human producedNov. 3, 200816CFC-12 released in troposphereCarried into stratosphere in the tropics by slow rising circulationCFC-12 photolyzed i

13、n stratosphere by solar UV, releasing ClCl catalytically destroys O3Cl reacts with CH4 or NO2 to form non-reactive HCl or ClONO2PolarlossChlorine PathwayNov. 3, 20081716%16%32%32%23%23%12%12%7%7%5%5%1%1%4%4%03400300020001000(CH3CCl3)(e.g., HCFC-22 = CHClF2)(CCl2FCClF2)Naturalsour cesOther gasesMethy

14、l chloroformHCFCsCFC-113Carbon tetrachloride (CCl4)CFC-11 (CCl3F)CFC-12 (CCl2F2)Methyl chloride (CH3Cl)0201510515%27-42%5-20%20%14%4%Methyl bromide (CH3Br)Halon-1211 (CBrCIF2)Halon-1301 (CBrF3)Other halonsVery-short lived gases (e.g., bromoform = CHBr3)Source Gases Cl is much more abundant than Br,

15、but Br is about 60 times more effective at O3 destructionFrom Ozone FAQ - see /ozone/faq.shtmlNov. 3, 200818Atmospheric Chlorine Trends from NOAA/ERL - Climate Monitoring DivisionUpdated Figure made by Dr. James Elkins from Trends of the Commonly Used Halons Below Published by Butl

16、er 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 years102 years5 years42 years85 yearsCFC-11 CCl4CFC-113CFC-12 CH3CCl3Nov. 3, 200819Polar Stratospheric CloudsCentral, Sweden January 14, 2003 - P. NewmanNov. 3,

17、200820Solomon et al. (1986), Wofsy and McElroy (1986), and Crutzen and Arnold (1986) suggest reactions on cloud particle surfaces as mechanism for activating ChlorineHClClONO2HNO3Cl2Cl2 is easily photolyzed by UV & blue/green lightHNO3 is sequestered on PSCAntarctic ozone hole theoryNov. 3, 2008

18、21Polar Ozone Destruction1. O3 + Cl ClO + O2Only visible light (blue/green) needed for photolyzing ClOOClNo oxygen atoms requiredNet: 2 O3 + h 3 O22 O33 O23. ClOOCl+h2 Cl+O22. 2 ClO + M ClOOCl + MNov. 3, 200822Antarctic Measurements Aurora over Halley Bay Station, Antarctica, 75.6S 26.5E Brunt Ice S

19、helf, Coats Land 105 days of continuous darkness, twice per year re-supply Population: 65 in summer, 15 in winterNov. 3, 200823October Antarctic Ozone pre-1985Nov. 3, 200824October Antarctic OzoneNov. 3, 200825TOMS - August 31, 2003Orange/Yellow indicates higher ozone levels. Blue colors indicate lo

20、w ozone valuesDark color over pole shows the extent of polar night, no ozone observationsAntarctic ozone hole is defined as the region covered by low ozone values 03/04/200226Ozone Hole AreaN. America1st observed SH major warming (2002)Sep. 21, 2008Sep. 30, 2008Nov. 3, 200827October Average Ozone Ho

21、leNov. 3, 200828March Average total ozoneNov. 3, 200829Arctic & Antarctic TrendsNov. 3, 200830Whats being done?Nov. 3, 200831What 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, prol

22、onged 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: /sunwise/uvindex.htmlNov. 3, 200832Atmospheric Chlorine Trends from NOAA/ERL - Climate Monitoring DivisionUpdated 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 years102 years5 years42 years85 yearsC