1. OCTOBER 2003 PROGRESS REPORT ICAP Phase 2 Harvard University Daniel J. Jacob (P.I.), Rokjin J. Park, Noelle Eckley, and Loretta J. Mickley November 7, 2003

2. GEOS-CHEM OXIDANT-PM 2001 SIMULATION FOR USE AS CMAQ BOUNDARY CONDITIONS - APPROACH: 1.Conduct a fully coupled oxidant-aerosol simulation on 2 o x 2.5 o horizontal resolution. 2. Archive a full set of 31 species concentrations including ozone, inorganic aerosols, and their precursors at 3-hr time resolution from the surface to 0.01 hPa. 3. GEOS-CHEM results archived will be processed for incorporation into the CMAQ simulations using linking tools developed by Daewon Byun. - CURRENT STATUS: 1.The simulation is in progress. The Jan-Jun 2001 period has already been completed and data are archived at Harvard. Monthly data files are 13 GB. 2.First week of data in January has been transferred to U. of Houston for processing into CMAQ IC/BC.

3. LINKING GEOS-CHEM AND CMAQ: TRANSBOUNDARY TRANSPORT OF CARBONACEOUS AEROSOLS FROM MEXICAN FIRES - APPROACH: conduct CMAQ (cb4-aero3) run for May1-31 1998 over CONUS 36 km domain with and without GEOS-CHEM boundary conditions. Run1: Use the standard profile initial and boundary conditions with no carbonaceous aerosol emission from wildfires in CONUS domain. Run2: Same as in Run 1 but with carbonaceous aerosol emission from wildfires in CONUS domain. Run3: Use the initial and boundary conditions updated every three hours from GEOS-CHEM with no carbonaceous aerosol emission from wildfires in CONUS domain. Run4: Same as in Run3 with carbonaceous aerosol emission from wildfires in CONUS domain. - CURRENT STATUS: Runs 1 and 2 are completed, Run 3 is in progress. Collaboration with Daewon Byun, U. Houston

4. IMPROVING THE GEOS-CHEM MERCURY SIMULATION Improved chemistry: slower reaction with OH Improved dry deposition mechanism Noelle Eckley, work in progress These improvements have led to more realistic values of TGM; annual model averages are now within 10- 20% of observations.

5. GEOS-CHEM MERCURY SIMULATION: COMPARISON WITH SITE MEASUREMENTS SITELAT.LONG.MEASUREDSIMULATED (GEOS-CHEM) MODEL ERROR Alert, Nunavut, Canada 82.5 N62.3 W1.541.73+11.7% Zeppelin, Norway78.54 N11.5 E1.561.88+20.6% Mace Head, Ireland53.7 N9.6 W1.731.43-17.3% Delta, British Columbia, Canada 49.10 N123.1 W1.721.43-16.7% Cheeka Peak, Washington, USA 48.3 N124.6 W1.561.43-8.0% St. Andrews, New Brunswick, Canada 45.08 N67.0 W1.431.60+12.0% Kejimujik, Nova Scotia, Canada 44.43 N65.2 W1.451.60+9.9% Cape Point, South Africa 34.35 S18.5 E1.391.31-5.2% Noelle Eckley, work in progress Simulated vs. measured TGM at selected sites, annual average ( ng/m 3 )

6. GEOS-CHEM MERCURY SIMULATION: NEXT STEPS Analyze model vs. measurements of RGM Incorporate Arctic mercury chemistry Include other oxidation pathways or reactions if necessary Noelle Eckley, work in progress

7. EFFECT OF CLIMATE CHANGE ON POLLUTANT VENTILATION GISS GCM simulations of CO and black carbon combustion tracers for 1990-2050 transient climate IPCC A1 scenario,  T o = 2 K from 1990 to 2050 Triangles indicate days of high CO. Extreme pollution events associated with lower boundary layer heights, but no significant difference between 2000 and 2050 heights. L.J. Mickley, work in progress Summertime frequency distributions of maximum daily boundary layer heights over northeast U.S. 1995-2002 2045-2052

8. Meteorology in NE associated with high CO and BC events includes average temperatures, high pressures, and clear skies 2050 2000 2 days before high CO Surf tempSpec humiditySurf press Low trop cloudsMid trop clouds Precipitation

9. Frequency distributions show higher extreme values of CO and/or black carbon tracers for 2050 NortheastSoutheast Upper midwestCalifornia 2050 2000

10. Effect of high pressure systems over southeastern Canada on U.S. pollution events High pressure system centered over SE Canada weakens westerlies over midwest, leads to high CO there. Surface pressure (mb), SE Canada Days of high CO over midwest Winds out of SE during high pollution events, consistent with high pressure over SE Canada We are currently investigating links between trends in surface pressure and pollution episodes over coming century. 2050 high CO days 2000 high CO days

11. PUBLICATIONS Publications acknowledging support from ICAP: –Fiore, A.M., D.J. Jacob, H. Liu, R.M. Yantosca, T.D. Fairlie, and Q. Li, Variability in surface ozone background over the United States: Implications for air quality policy, J. Geophys. Res., in press, 2003. – Park, R. J., D. J. Jacob, M. Chin and R. V. Martin, Sources of carbonaceous aerosols over the United States and implications for natural visibility, J. Geophys. Res., 108, 4355, 2003. –Fiore, A.M., D.J. Jacob, B.D. Field, D.G. Streets, S.D. Fernandes, and C. Jang, Linking ozone pollution and climate change: The case for controlling methane, Geophys. Res. Lett., 29(19), 1919, 2002. Manuscript in preparation (draft available): – Park, R.J., et al., Natural and transboundary influences on ammonium-sulfate-nitrate aerosols in the United States: implications for visibility, for submission to J. Geophys. Res.