1. CO over South America Modeling inter annual variability of biomass burning emissions Pim Hooghiemstra & Maarten Krol 28 November 2011 – TM meeting

2. Motivation Inter annual variability is observed in MOPITT columns over the Amazon region.

3. Goal Robust monthly total CO emissions on high resolution for 2006 – 2010 over South America Using TM5-4D-Var with 1 o x1 o zoom over South America Prior from EDGARv4.1, GFED3.1, TM4-Crete MOPITT columns / NOAA surface observations

4. Prior simulation vs observations Emissions seem too low a priori (large region) Over main BB regions, prior is too high in 2007 and 2010

5. Posterior fit with MOPITT 4D-Var system brings model simulation close to observations. Fit is very good for large regions, a bit less for small regions.

6. Emissions 1 o x1 o region Large variability in emissions from year to year Emissions increase for all months

7. Spatial patterns 2007 & 2010: Emissions go down for deforestation regions Brazil Other years, emissions increase (both BB and other sources)

8. Validation with NOAA Much too high => assimilate NOAA obs also

9. Bias correction A bias correction is needed to fit NOAA and MOPITT

10. Fit with data Fit with NOAA improves greatly! Fit with MOPITT remains good!

11. Effect on inferred emissions Effect is only small

12. Sensitivity studies Emission estimates are robust Using GFED3-2009 for 2010 makes a large difference NOAA only inversion yields too high biomass burning emissions in September and too low background emissions

13. Conclusions (1) Robust IAV in BB emissions: Peak month emissions vary from 28 Tg CO in 2009 to 67 Tg CO in 2007. BB emissions of GFED3.1 are too high in main deforestation regions in Brazil in 2007 & 2010. In other years, GFED3.1 seems a bit too low. Remark: difficult to quantify, we only optimize total. What about errors in the model?

14. Conclusions (2) Inferred emissions sensitive to total prior BB emission. Bias correction is necessary to fit both MOPITT & NOAA observations. No significant difference in optimized emissions and fit with MOPITT, fit with NOAA improves significantly.