1. Simulation Experiments for GEO-CAPE Regional Air Quality GEO-CAPE Workshop September 22, 2009 Peter Zoogman, Daniel J. Jacob, Kelly Chance, Lin Zhang, Philippe Le Sager, Arlene Fiore This work is supported by the NASA Atmospheric Composition Modeling and Analysis Program

2. Observing System Simulation Experiment a priori = GEOS-Chem model “Truth” = MOZART model a posteriori = GEOS-Chem + assimilation of synthetic observations  attempt to reproduce true atmosphere Developed OSSE capability for regional scale problems First application is to determine GEO-CAPE measurement requirements for surface ozone

3. Simulation Models Severe test due to opposite biases at 700 hPa and surface MOZART (1.9 o x1.9 o, NCEP) GEOS-Chem (1 o x1 o, GEOS-3) “Truth” a priori JULY 2001 700 hPa Below 1 km ppbv

4. Methods Synthetic Observations – apply averaging kernel to “truth” Remove cloudy scenes Data Assimilation – Kalman Filter Includes spatial covariance of 1 km in vertical, 300 km in horizontal (will be informed by sensitivity team) Error is evolved and transported as a passive tracer Model Error computed by comparison to ozonesonde GEOS-Chem error found to be 25% Instrument smoothing error assumed to be diagonal, 10% TES O 3 AK North American 1 o x1 o Nested Grid

5. Results at 700 hPa GEOS-Chem mean absolute bias: 7.4 + 4.1 ppbv GEOS-Chem + Hourly Obs: 2.7 + 2.0 ppbv Hourly observations (daytime clear-sky only) provide successful correction, much better than daily observations Mean July 2001 Ozone GEOS-Chem + Daily Obs: 5.6 + 3.5 ppbv ppbv

6. Results below 1 km GEOS-Chem mean absolute bias: 4.3 + 3.3 ppbv Mean July 2001 Ozone GEOS-Chem + Hourly Obs: 3.4 + 2.7 ppbv GEOS-Chem + Daily Obs: 4.1 + 3.0 ppbv TES sensitivity to boundary layer is insufficient to correct model significantly at the surface -- need to do better to inform ozone surface air quality ppbv

7. Sensitivity by Adjoint Adjoint model – receptor based rather than source based approach Sensitivity of surface ozone to ozone produced at each vertical layer – tool to understand OSSE results Surface ozone primarily sensitive to production below 2 km; this supports simulation results Accumulated surface O 3 sensitivity for Boston

8. Summary and Future Work TIR measurements not sufficient for boundary layer ozone Multispectral is needed! Developed a framework for testing prospective instrumentation – can be applied as new sensor configurations are proposed Frequency of observations, observation domain, nighttime observations GEOS-Chem resolution will increase – 10 km by end 2010 Use CMAQ ozone for higher resolution/different “truth” Integration of surface sites Perform forecasting OSSEs Expand to combine observations of other species NO x, CO, HCHO Required frequency may be different for different species Define requirements for climate forcing and intercontinental transport