N. Krotkov 1 , S. Carn 2 , A. Krueger 2 , P. K. Bhartia 3 , K. Yang 4

1. 1st Year of SO2 data from OMI • N. Krotkov1, S. Carn2, A. Krueger2 , P. K. Bhartia3 , K. Yang4 • Goddard Earth Sciences and Technology (GEST) Center, UMBC, Baltimore, MD • Joint Center for Earth Systems Technology (NASA/UMBC), UMBC • Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD • SSAI, Lanham , MD

2. The AURA OMI SO2 volcanic data set will continue the TOMS SO2 record, which covers a quarter-century: http://toms.umbc.edu

3. OMI SO2 algorithm An OMI SO2 Band Residual Difference ( BRD) algorithm uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3) [Bhartia et al 2002]

4. OMI SO2 image of the Anatahan (Mariana Islands) Anatahan (Mariana Islands) eruption cloud on April 7, 2005, produced by an explosive eruption on April 6. White regions are meteorological clouds.

5. Anatahan plume in July  2005, including the passage of some typhoons.

6. OMI SO2 image of passive degassing from Ambrym volcano, Vanuatu (16.25ºS, 168.12ºE) on February 20, 2005.

7. SO2 emissions from lignite-burning power plants in the Balkan region SO2 enhancements observed by GOME in February 1998 [Eisinger and Burrows, GRL 1998]. SO2 enhancements detected by OMI in February 2005

8. SO2 burdens over China • 70% of China’s energy is derived from coal burning • SO2 emissions increased at a rate 35%/decade in 1979-2000 • China’s sulfate aerosol loading has increased by 17%/decade in 1979-2000 [Massie, Torres and Smith 2004] • 65,000 SO2 tons/day emitted in 1995 [Streets & Waldhof, 2000]

9. Anthropogenic SO2 burdens in Asia • Norislk Nickel is one of Russia’s heaviest industrial polluters • World’s biggest producer of nickel and palladium • Plans to reduce SO2 emissions by 80-90% by 2015

10. SO2 emissions associated with oil and gas refining in the Persian Gulf (Kuwait, Saudi Arabia, Iran, UAE) • Outgassing flares from oil fields in the Gulf produce detectable SO2

11. Major SO2 sources in Africa: Nyiragongo (DR Congo) GOME observation of the time evolution of the SO2 plume over Nyamuragira volcano during its December 1996 eruption. • More than 90% of South Africa's electricity is generated by the combustion of coal • Coal-fired power plants not required to use scrubbers to remove sulfur from emissions OMI: South African power plants (e.g., near Johannesburg); copper smelting

12. South East Asia Anatahan (Mariana Is) Manam (PNG) Ambrym (Vanuatu)

13. Surface UV from TOMS/OMI measurements • N. Krotkov1, J. Herman2, P.K. Bhartia2 , A. Tanskanen3 , A. Arola4 • Goddard Earth Sciences and Technology (GEST) Center, UMBC, Baltimore, MD • Laboratory for Atmospheres, NASA GSFC, Greenbelt, MD • Finnish Meteorological Institute , Helsinki, Finland • Finnish Meteorological Institute , Kuopio, Finland

14. OMI Science questions • Is the ozone layer recovering ? • What are sources and distributions of aerosols and trace gases that affect global air quality? • What are the roles of tropospheric ozone and aerosols in climate change? • What are the causes of surface UV-B change ? Levelt et al “ Science objectives of Ozone Monitoring Instrument “ in IEEE- TGRS AURA special issue

15. UV products: noon irradiance + Daily CIE dose(305nm, 310nm, 324nm, 380nm, CIE - UV index) 324nm 305nm 380nm Erythemal – UV index

16. Current Applications of TOMS/OMI UV data 1. Sun burn and skin cancer PHS, NIH, WHO 2. Eye cataracts PHS, NIH, WHO 3. Plant damage - Crop yields USDA 4. Food chain - Land – Oceans USDA, NOAA 5. Effect on insect population NIH, PHS, WHO

17. TOMS/OMI UV algorithm OMI Ozone Sun: Fo ( ~ 3% uncertainty ) Clouds and non-absorbing aerosols are well corrected Clouds Fc ~ FO3(1 – R) Absorbing aerosols are still a major problem Aerosols

18. Cloud correction algorithm (CT) ISCCP TOMS daily Satellite CT estimate 10 day monthly UV- Williams et al GRL 2004 (1:1) (1:1) PAR - Dye et al GRL 1995 Ground CT measurement

19. Clouds over snow correction • Surface albedo is a crucial parameter for estimation of the surface UV in regions with temporary snow or ice. • OMI UV algorithm applies an albedo climatology derived from the N7/TOMS reflectivity data using the moving time window method. • The accuracy of the surface UV estimates for high latitudes has improved.However, the estimates for albedo transient periods are still uncertain. http://promote.fmi.fi/MTW_www/MTW.html

20. The TOMS-Brewer difference for erythemally weighted UV irradiance and for UV irradiance at 305, 310, and 324 nm. Summer noon values for mostly clear sky conditions (TOMS reflectivity <0.2)

21. The TOMS-Brewer difference for erythemally weighted summer noon UV irradiance for mostly clear sky conditions (TOMS reflectivity <0.2) Urban locations

22. Long-range ABSORBING aerosol transport in free troposphere is uniquely tracked by OMI/TOMS Aerosol Index (AI) US AI cannot detect boundary layer UV absorbing aerosols resulting in overestimates of UV irradiance that are frequently 10% and sometimes 20%. India Southeast Asia TOMS AI examples of high-density smoke aerosols that affect various coastal regions in the US, India, and Southeast Asia. Lesser amounts of smoke, dust, and carbonaceous aerosols frequently cause overestimations of UV irradiance if ignored.

23. UV reduction due to absorbing aerosols in free troposphere (dust, smoke) is corrected using positive AI >0.5 data Industrial aerosols close to the ground are not seen in AI data (AI <0), so they are treated as thin clouds, which leads to positive UV bias

24. Ground AEROSOL absorption measurements UV Multifilter Rotating Shadowband Radiometer AERONET CIMEL sun-sky radiometers Brewer spectrometer ozone, SO2, NO2 [Cede and Herman] Since 2002, the NASA TOMS, AERONET and USDA UVB programs have shared equipment, personnel and analysis tools to quantify aerosol UV-VIS absorption using a combination of ground based radiation measurements.

25. TOMS UV Correction for Absorbing Aerosols in Greenbelt, USA 1 TOMS/Ground UV ABS at 325nm ABS at 325nm The ratio between satellite estimated (by TOMS UV algorithm7-10) and measured (by UVMFRSR) total (direct plus diffuse) surface UV irradiance at 325nm versus aerosol absorption optical thickness at 325nm inferred from combined UV-MFRSR and AERONET measurements at NASA/GSFC site. The line shows theoretical relationship derived from radiative transfer modeling10. Time series of aerosol absorption optical thickness tabs at 368nm, derived from 17 months UV-MFRSR operation at NASA GSFC site in Maryland, US. The data are for cloud-free and snow-free conditions and tabs(440)>0.1. Individual tabs(368) values were averaged over 1-hour period of time within ±60min of the AERONET inversion. 1Krotkov et al. Opt. Engineering 2005

26. TOMS UV Correction for Absorbing Aerosols in 2 urban sites 1 SZA=20-30 SZA=40-50 SZA=60-70 The ratio of TOMS to Brewer irradiance at 324nm against aerosol absorption optical thickness in Thessaloniki, Greece The ratio of TOMS to Brewer irradiance at 324nm against aerosol absorption optical thickness at Ispra, Italy 1Arola et al. accepted JGR 2005

27. Future Applications of OMI data 1. Global mapping of PAR (400-700nm) 2. Actinic flux profile and J-rates for photochemistry models3. UV irradiance on tilted surfaces 4. Global mapping of underwater UV-PAR irradiance 5. Global primary production estimates 6. Global carbon cycle models

28. Erythemal Irradiance Trend 1980 to 2002 O3 R360

29. 305 nm Irradiance Trend 1980 to 2002 O3 R360

30. What are the causes of surface UV-B change ? • Is the ozone layer recovering ? • Are there trends in cloudiness ( climate change) ? • What are sources and distributions of absorbing aerosols and trace gases? • What are the roles of tropospheric ozone and aerosols in modifying UV irradiance and actinic flux? Levelt et al “ Science objectives of Ozone Monitoring Instrument “ in IEEE- TGRS AURA special issue