GEOS-CHEM global model of tropospheric chemistry (www-as.harvard/chemistry/trop/geos)

1. GEOS-CHEM global model of tropospheric chemistry(www-as.harvard.edu/chemistry/trop/geos) • assimilated meteorological data from NASA DAO, 1988-2001 • 1ox1o- 4ox5o horizontal resolution, 20-48 layers in vertical • used by groups at Harvard, Duke, U. Washington, Rutgers, JPL, BNL, EPFL, Toulouse, Aquila; standard versions and benchmarks maintained at Harvard RECENT AND CURRENT APPLICATIONS: • Tropospheric ozone : global budget, Asian outflow, U.S. air quality, Middle East, transatlantic transport, tropics (TOMS), interannual variability, trends • Carbon monoxide: global and regional budgets, interannual variability • Aerosols: sulfate-organics-dust-sea salt, phase transitions • Stratospheric ozone: coupling with troposphere • Carbon dioxide: source/sink information from correlations with chemical tracers • Organics: hydrocarbons, oxygenated organics, nitriles, methyl halides • Satellite retrievals, inversions, chemical data assimilation: CO, CO2, ozone, formaldehyde, NO2 • Chemical forecasting: TRACE-P

2. GEOS-CHEM CHEMICAL FORECASTING IN TRACE-P (Feb 22 – Apr 10, 2001) • 5-day GEOS-3 forecast fields from DAO (2ox2.5o, 2x/day) and daily assimilated fields (1ox1o) were used to drive off-line CO simulation • Forecasting system (“TRAPS”) was fully automated: • GEOS data download and processing • Update of initial CO fields by GEOS-CHEM using assimilated GEOS fields • 4-day CO forecast simulation • Posting of 3-D CO fields, movies, maps on ftp site • Reliability of forecasting system was ~100% 0Z: start of forecast 14Z: forecast available from DAO DAY -1 0 1 2 16Z: GEOS-CHEM forecast product sent to TRACE-P team GEOS-CHEM update of CO initial condions using assimilated GEOS fields GEOS-CHEM forecast

3. Satellite data in near-real time: MOPITT TOMS SEAWIFS AVHRR LIS TRACE-P EXECUTION Stratospheric intrusions FLIGHT PLANNING Long-range transport from Europe, N. America, Africa 3D chemical model forecasts: - ECHAM - GEOS-CHEM - CFORS - Meso-NH -LaRC/U. Wisconsin ASIAN OUTFLOW Boundary layer chemical/aerosol processing DC-8 P-3 PACIFIC • Emissions • Fossil fuel • Biomass burning • Biosphere, dust ASIA PACIFIC

4. FRONTAL OUTFLOW OF CO DURING TRACE-P DC-8 Hong Kong local 1, March 7 Lifting ahead of front Observed (G.W. Sachse, NASA/LaRC) Boundary layer outflow behind front Cold front GEOS-CHEM forecast (Harvard)

5. SIMULATED vs. OBSERVED CO IN TRACE-P:bias and R2 vs. altitude (5000 aircraft observations) Mat Evans, Harvard ALTITUDE, km Mean model/observed CO (bias) R2 in 1-km bins

6. How reliable were the CO forecasts during TRACE-P? What errors should be applied in the interpretation of these forecasts? Errors in GEOS-CHEM forecasts during TRACE-P (Isabelle Bey, EPFL) Examine r2 statistics for forecasts vs. observations DISPLACEMENT ERROR SMEARING ERROR downward displacement upward displacement Increasing vertical smearing Forecast altitude

7. PROPOSED Harvard/UW CHEMICAL FORECAST SUPPORT FOR NOAA 2K2 • Operate TRAPS system as in TRACE-P with GEOS-3 meteorological forecasts from NASA/DAO driving a global GEOS-CHEM simulation off-line • Spatial resolution of forecasts: 2ox2.5o, 48 vertical levels • Frequency of forecasts: 1x/day for entire mission • Species to be forecast: at least Asian and N. American CO, others to be discussed • Personnel • At DAO: Gi-Kong Kim, Rob Lucchesi • At Harvard: Bob Yantosca, Qinbin Li, Daniel Jacob • In the field: Lyatt Jaeglé, Qinbin Li