1. USE OF GEOS-CHEM BY SMITHSONIAN ASTROPHYSICAL OBSERVATORY AND DALHOUSIE UNIVERSITY Randall Martin Mid-July SAO Halifax, Nova Scotia

2. RETRIEVAL AND INTERPRETATION OF SATELLITE OBSERVATIONS OF THE TROPOSPHERE InstrumentCoverageTypical resolution (km) GOME1995-40x320 SCIAMACHY2002-30x60 OMI2004-13x24 NO 2, HCHO, O 3, SO 2, BrO

3. GEOS-CHEM MODEL IDENTIFIES FAVORABLE REGIONS TO DETERMINE STRATOSPHERIC COLUMN AND INSTRUMENT BIASES Martin et al., 2002

4. SLANT COLUMNS OF TROPOSPHERIC NO 2 FROM GOME 1996 Martin et al., 2002

5. USE GEOS-CHEM TO CALCULATE AMFs FOR NO 2 and HCHO FOR EVERY SATELLITE VIEWING SCENE SATELLITE DATA SLANT COLUMN GEOS-CHEM GLOBAL 3-D MODEL OF TROPOSPHERIC CHEMISTRY: provides shape factors AMF VERTICAL COLUMN Best information applied to each scene Consistency in comparing model and observed columns ADVANTAGES OF 3-D MODEL APPROACH FOR COMPUTING AMFs spectral fit LIDORT RAD.TRANSFER MODEL: provides scattering weights

6. GOME Tropospheric NO 2 GEOS-CHEM Tropospheric NO 2 10 15 molecules cm -2 Martin et al., 2003 OPTIMIZE INVENTORY USING A PRIORI BOTTOM-UP AND GOME TOP-DOWN INFORMATION Determine NOx Emissions from GOME Observations Using GEOS-CHEM to Provide Information on the NO x /NO 2 Ratio and NO x Lifetime

7. IN THE QUEUE: GEOS-CHEM NO X EMISSIONS WILL REFLECT ADDITIONAL GOME INFORMATION Annual mean ratio (A posteriori / A priori) Martin et al., 2003

8. EXAMINE SEASONAL VOC EMISSIONS USING GOME AND GEOS-CHEM HCHO COLUMNS: SAO Role in Retrieval, AMFs, and Model Simulation MAR APR MAY JUN JUL AUG SEP OCT Abbot et al., 2003

9. EL NINO INTERANNUAL VARIABILITY IN OZONE: DIFFERENCE BETWEEN OCT 97 AND OCT 96 Chandra et al. [2002] TOMS

10. TOMS/MLS TROPOSPHERIC OZONE PROVIDES FURTHER EVIDENCE THAT OZONE IS TOO HIGH OVER INDIA Dobson Units for March, April, May TOMS/MLS GEOS-CHEM 30 N 30 S 30 N 30 S Chandra et al., 2003

11. OPERATIONAL HCHO RETRIEVAL ALGORITHM FOR OMI Uses Monthly Mean HCHO Shape Factors from GEOS-CHEM SUPPORT FOR GMI Provide GEOS-CHEM resultsProvide GEOS-CHEM results for various simulations (i.e. with and without aerosols) Assist interpretation of model results EVALUATE GEOS-CHEM SIMULATION OF NO X With In Situ NO 2 Measurements from SOS (1999) and TEXAQS (2000)

12. FUTURE USE OF GEOS-CHEM AT DALHOUSIE Likely local platforms: 8-Processor 1.2 GHz Sun Fire 3800 (Works!, credit Yantosca) 20-Processor 700 MHz SGI Origin 350 Continued support for GMI Real-time HCHO and NO 2 Retrievals from SCIAMACHY for INTEX Use Shape Factors from GEOS-CHEM Retrieval and Interpretation of HCHO, NO 2, SO 2, O 3, BrO, CO from TOMS / GOME / SCIAMACHY / OMI Interpretation of satellite observations from MOPITT, MODIS, TES, … and aircraft missions such as INTEX, ITCT-2K4, …