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SO 2 Budgets

A New Method for the Retrieval of Upper Troposphere/Lower Stratosphere Sulfur Dioxide from Global Long-term TOVS Measurements Fred Prata, CSIRO Atmospheric Research, Australia John Bates, NOAA-ETL, USA Darren Jackson, NOAA-ETL, USA. SO 2 Budgets. Source SO 2 SO 4

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SO 2 Budgets

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  1. A New Method for the Retrieval of Upper Troposphere/Lower Stratosphere Sulfur Dioxide from Global Long-term TOVS Measurements Fred Prata, CSIRO Atmospheric Research, Australia John Bates, NOAA-ETL, USA Darren Jackson, NOAA-ETL, USA ITSC-XII Lorne, Victoria

  2. SO2 Budgets Source SO2 SO4 Fossil-fuel combustion +industry 70 2.2 Biomass burning 2.8 0.1 Oceans – 40–320 Plants+soils – 2–4 Volcanoes 7–8 2–4 Units: Tg(S) yr-1 Source: Berresheim et al. (1995) ITSC-XII Lorne, Victoria

  3. The volcanic plume from Hekla on 29th of February ITSC-XII Lorne, Victoria

  4. Infrared image (11 µm) x Encounter ITSC-XII Lorne, Victoria

  5. Difference image (11-12 µm) x Encounter ITSC-XII Lorne, Victoria

  6. 7.3 µm image x Encounter ITSC-XII Lorne, Victoria

  7. 27 D.U. ITSC-XII Lorne, Victoria

  8. 24 D.U. TOMS SO2 (m atm-cm) 30 27 February, 2000 18 6 ITSC-XII Lorne, Victoria

  9. MODIS channels and SO2 Line Strengths ITSC-XII Lorne, Victoria

  10. SO2 line strengths Transmission Brightness temperature (t.o.a) Difference (Kelvin) ITSC-XII Lorne, Victoria

  11. Weighting functions and transmission vs absorber amount ITSC-XII Lorne, Victoria

  12. MODTRAN simulations ITSC-XII Lorne, Victoria

  13. The Retrieval Scheme: • Get radiances for HIRS channels 8 (11.11 µm), 11 (7.34 µm) and 12 (6.76 µm) • Synthesise 7.3 µm channel from the 6.7 µm and 11.1 µm channels by linear interpolation in radiance • Compute difference DT=T*7.3-T7.3 (T* is the synthetic BT) • Exclude pixels with T11 < 220 K • Compute SO2 amount using model from RT simulations: • Log10[SO2]=c0+c1DT+c2DT2+c3DT3 ITSC-XII Lorne, Victoria

  14. ITSC-XII Lorne, Victoria

  15. ITSC-XII Lorne, Victoria

  16. ITSC-XII Lorne, Victoria

  17. ITSC-XII Lorne, Victoria

  18. MODIS retrieval for Hekla, Feb 2000 eruption Approximate aircraft track ITSC-XII Lorne, Victoria

  19. SOLVE (NASA DC-8) in situ SO2 measurements and MODIS retrievals show good agreement Integrated across plume: SOLVE=248 ppmV MODIS=241 ppmV ITSC-XII Lorne, Victoria

  20. ITSC-XII Lorne, Victoria

  21. ITSC-XII Lorne, Victoria

  22. TOVS TOMS ITSC-XII Lorne, Victoria

  23. TOVS TOMS ITSC-XII Lorne, Victoria

  24. Eruption of Cerro Hudson, southern Chile 7-27 August, 1991 ITSC-XII Lorne, Victoria

  25. Very cold scene temperatures (T<220 K) cause anomalies in retrieval scheme ITSC-XII Lorne, Victoria

  26. Anomalies are removed by excluding pixels where T11< 220 K SO2 above very cold surfaces difficult to retrieve by this method ITSC-XII Lorne, Victoria

  27. ITSC-XII Lorne, Victoria

  28. Different orbits give different mass loadings, but very similar mass densities NOAA-10-> 0.653 t km-2 (mass loading=0.98 Mt) NOAA-11-> 0.658 t km-2 (mass loading=0.33 Mt) NOAA-12-> 0.655 t km-2 (mass loading=0.86 Mt) ITSC-XII Lorne, Victoria

  29. Mt St Helens, May, 1980 ITSC-XII Lorne, Victoria

  30. Ash detection ITSC-XII Lorne, Victoria

  31. SO2detection ITSC-XII Lorne, Victoria

  32. Pinatubo 15 June - 15 July, 1991 ITSC-XII Lorne, Victoria

  33. CONCLUSIONS • SO2 in the lower stratosphere and upper troposphere can be retrieved from the HIRS 7.3 µm channel • Day/night, global, long-term (>22 years) capability • Ozone/SO2 studies possible • Ash vs SO2 vs H2SO4 discrimination possible • Impact on humidity soundings using 7.3 µm channel • (RT models should consider SO2 absorption) • Climate applications - radiative effects using all TOVS channels ITSC-XII Lorne, Victoria

  34. El Chichon, March 1982 ITSC-XII Lorne, Victoria

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