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

Typical resolution (km) RETRIEVAL AND INTERPRETATION OF SATELLITE OBSERVATIONS OF THE TROPOSPHERE Instrument Coverage Typical resolution (km) GOME 1995- 40x320 SCIAMACHY 2002- 30x60 OMI 2004- 13x24 NO2, HCHO, O3, SO2, BrO

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

SLANT COLUMNS OF TROPOSPHERIC NO2 FROM GOME 1996 Martin et al., 2002

USE GEOS-CHEM TO CALCULATE AMFs FOR NO2 and HCHO FOR EVERY SATELLITE VIEWING SCENE GEOS-CHEM GLOBAL 3-D MODEL OF TROPOSPHERIC CHEMISTRY: provides shape factors LIDORT RAD.TRANSFER MODEL: provides scattering weights AMF spectral fit SATELLITE DATA SLANT COLUMN VERTICAL COLUMN Best information applied to each scene Consistency in comparing model and observed columns ADVANTAGES OF 3-D MODEL APPROACH FOR COMPUTING AMFs

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 NOx/NO2 Ratio and NOx Lifetime GOME Tropospheric NO2 GEOS-CHEM Tropospheric NO2 Martin et al., 2003 1015 molecules cm-2

IN THE QUEUE: GEOS-CHEM NOX EMISSIONS WILL REFLECT ADDITIONAL GOME INFORMATION Annual mean ratio (A posteriori / A priori) Martin et al., 2003

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

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

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

OPERATIONAL HCHO RETRIEVAL ALGORITHM FOR OMI Uses Monthly Mean HCHO Shape Factors from GEOS-CHEM SUPPORT FOR GMI Provide GEOS-CHEM results for various simulations (i.e. with and without aerosols) Assist interpretation of model results EVALUATE GEOS-CHEM SIMULATION OF NOX With In Situ NO2 Measurements from SOS (1999) and TEXAQS (2000)

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 NO2 Retrievals from SCIAMACHY for INTEX Use Shape Factors from GEOS-CHEM Retrieval and Interpretation of HCHO, NO2, SO2, O3, BrO, CO from TOMS / GOME / SCIAMACHY / OMI Interpretation of satellite observations from MOPITT, MODIS, TES, … and aircraft missions such as INTEX, ITCT-2K4, …