1. Tropospheric NO2 Ronald van der A, Michel Van Roozendael, Isabelle De Smedt, Ruud Dirksen, Folkert Boersma KNMI and BIRA-IASB Beijing, 23 October 2009

2. Monitoring by satellite UV-VIS retrievals NO2 SO2 HCHO O3 Infrared retrievals CO CH4 ATSR retrievals Aerosols

4. Shipping routes Seasons averaged over available data set

5. Trend in tropospheric NO 2 (1996-2006) Tehran, Delhi Calcutta van der A et al., JGR, 2008

6. Continuation with OMI (2004 - now)

7. Overpass files

8. Summary Tropospheric NO2  GOME/SCIAMACHY/OMI/GOME-2 NO2 data available for 1996-today.  Data is used for trend analysis, shipping routes, source identification, diurnal cycle.  Monitoring of China with SCIAMACHY/GOME-2 (overpass at 10.00/9.30 AM ) and OMI (overpass at 13.30 PM)  Overpass files for GOME-2 and OMI pixels within 50 km from station.

9. GOME tropospheric O3 columns R. van der A, J. de Laat, J. van Peet, O. Tuinder (KNMI)

10. Directly measuring tropospheric O3 from space: GOME OPERA algorithm (Ozone ProfilE Retrieval Algorithm) Non-linear Optimal Estimation [Rodgers], iterative, use of a-priori Limited height information [Degrees of Freedom for Signal] About 5 independent pieces of vertical information  Smoothing of actual profile !!  about 1 piece of tropospheric information [cf. Liu et al., JGR, 2005] Courtesy J. Landgraf, SRON

11. Comparison at Antarctic research station Neumayer Neumayer: Weekly sonde sounding During ozone hole up to 3 times a week Collocation criteria Distance <= 300 km Time difference max 12 hour

12. Alfred Wegener Institute for Polar and Marine Research (AWI)

14. Assimilation of GOME-2 ozone profiles UV/VIS ozone profile assimilation with TM5 model –single O3 tracer based on Cariolle linearized O3 chemistry scheme [Cariolle and Teyssedre; ACP] –ECMWF meteo data. –assimilation of O3 profile using Kalman filter [Eskes,Segers] –Subtracting integrated stratopsheric ozone from total column ozone

15. Tropospheric Ozone data GOME tropospheric columns:  Data set complete  Low resolution => low quality  Small improvements possible GOME-2 tropospheric profiles:  Data set is available  Data is difficult to interpret: averaging kernel and a-priori profile needed  Validation results not so good GOME-2 tropospheric columns:  New approach by assimilating of ozone profiles  Data set not available yet  Long processing time

16. Summary tropospheric ozone Ozone profile datasets available Processing is time consuming Usefull feedback from validation done by MariLiza Outlook: Data assimilation of profiles is under development