1. ICDC7, Boulder, 26-30 September 2005 CH 4 TOTAL COLUMNS FROM SCIAMACHY – COMPARISON WITH ATMOSPHERIC MODELS P. Bergamaschi 1, C. Frankenberg 2, J.F. Meirink 3, M. Krol 1, F. Dentener 1, M. van Weele 3,T. Wagner 2, U. Platt 2, S. Koerner 4, M. Heimann 4, 1 European Commission Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy 2 Institute for Environmental Physics, University of Heidelberg, Heidelberg, Germany 3 Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands 4 Max Planck Institute for Biogeochemistry, Jena, Germany

2. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY absorption spectra of solar radiation (near-IR) -> high sensitivity also towards the surface Main challenge: Target precision / accuray ~ 1%

3. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY - validation ground based FTIR (total column measurements) NDSC network - very few stations (~11) only; no coverage of tropical source regions - FTIR precision (~3%), accuracy (~7%) [Dils et al., 2005] comparison with other satellites currently no other CH 4 retrievals available (except some exploratory retrievals from IMG/ADEOS (1997) inverse modelling using high precision / accuracy surface insitu / flask measurements (  CH 4 ~ 0.1%) -> global 3D CH 4 fields alternative approach:

4. ICDC7, Boulder, 26-30 September 2005 model - validation validation of models (and bottom-up emission inventories) in particular over source regions which are not well sampled by the surface measurements Final objective: Better quantification of CH 4 emissions opposite view:

5. ICDC7, Boulder, 26-30 September 2005 TM5 model TM5 model – atmospheric zoom model offline atmospheric transport model meteo from ECMWF global simulation 3 o x 2 o zooming 1 o x 1 o (North America, South America, Europe, Africa, Asia, Australia) http://www.phys.uu.nl/~tm5/ [Krol et al., 2005]

6. ICDC7, Boulder, 26-30 September 2005 TM5 simulations inversion based on groundbased monitoring sites synthesis inversion optimizing: - monthly emissions - 11 source categories - 7 global regions for wetlands - 5 global regions for biomass burning ground based background monitoring sites (NOAA/CMDL)

7. ICDC7, Boulder, 26-30 September 2005 TM5 inverse simulations examples for some monitoring sites simulation of global CH 4 consistent with surface monitoring sites (background sites) 01 Jan31 Dec

8. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - global 2003 average column averaged CH 4 [ppb] TM5 SCIA

9. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - global 2003 average column averaged CH 4 [ppb] TM5 SCIA N-S gradient ~100 ppb consistent between SCIA and TM5

10. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - global 2003 average column averaged CH 4 [ppb] TM5 SCIA Enhanced CH 4 over SouthEast Asia and tropical regions (S.America, Africa)

11. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - Asia 04-06 2003 TM5 SCIA

12. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - Asia 07-09 2003 TM5 SCIA

13. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - Asia 10-12 2003 TM5 SCIA

14. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - South America 01-03 2003 TM5 SCIA

15. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - South America 04-06 2003 TM5 SCIA

16. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - South America 07-09 2003 TM5 SCIA

17. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - South America 10-12 2003 TM5 SCIA

18. ICDC7, Boulder, 26-30 September 2005 South America 01-03 2003 JK CH 4 emission from wetlands: J. Kaplan [2005] spatial distribution of wetlands based on GLC2000 TM5 SCIA

19. ICDC7, Boulder, 26-30 September 2005 South America 01-03 2003 BW CH 4 emission from wetlands: Walter et al. [2001] spatial distribution of wetlands based on [Matthews and Fung, 1987] TM5 SCIA

20. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5: global std, bias std bias daily SCIA retrievals vs. TM5 (global over land)

21. ICDC7, Boulder, 26-30 September 2005 Conclusions SCIAMACHY provides view on global CH 4 distribution Enhanced CH 4 over SouthEast Asia, and tropical regions of South America and Africa (  CH 4 up to ~70 ppb) Comparison with inverse simulations, optimized towards insitu observations: Background regions: reference for validation of SCIAMACHY retrievals Source regions: Different model scenarios yield significantly different CH 4 distributions -> rather check of consistency than strict validation major uncertainty: CH 4 emissions from wetlands overall std: 23.6 ppb (1.4%) - upper estimate of SCIA precision potential (seasonal) bias (in particular over Australia (~20 ppb)) average N-S gradient (~100 ppb) consistent between SCIAMACHY and TM5

22. ICDC7, Boulder, 26-30 September 2005 Thank you !

23. ICDC7, Boulder, 26-30 September 2005 Supporting Material

24. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY / ENVISAT SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) SCIAMACHY on ENVISAT altitude: 800 km 14 orbits per day full global coverage: every 6 days CH 4 : 1563-1585 nm CO 2 : 1631-1670 nm (O 2 : 760 nm)

25. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY VCD->VMR variability of total columns:  CO 2 ~ 1/3  CH 4 Conversion vertical column densities (V) [molec / cm 2 ] -> column averaged mixing ratios (VMR) [ppb] use of CO 2 instead of O 2 for determination of total vertical column of dry air [Frankenberg et al., Science, 2005] -> very similar light path distribution (scattering) CO 2 VMR from TM3 column averaged CH 4 mixing ratio [ppb]

26. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY - averaging kernels [Frankenberg et al., 2005]

27. ICDC7, Boulder, 26-30 September 2005 SCIAMACHY vs. TM5 - global (incl. ocean)

28. ICDC7, Boulder, 26-30 September 2005 emission inventories for TM5 simulations bottom-up emission inventories used as priori emissions for inverse TM5 simulations: