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Asian Air Pollution Export and Aerosol-Regional Climate Interactions

Asian Air Pollution Export and Aerosol-Regional Climate Interactions. Yang Zhang, Kai Wang, and Yao-Sheng Chen. Air Quality Forecasting Laboratory Dept. of Marine, Earth and Atmos. Sci., NC State Univ., Raleigh, NC. Carey J. Jang and Sharon Phillips

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Asian Air Pollution Export and Aerosol-Regional Climate Interactions

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  1. Asian Air Pollution Export and Aerosol-Regional Climate Interactions Yang Zhang, Kai Wang, and Yao-Sheng Chen Air Quality Forecasting Laboratory Dept. of Marine, Earth and Atmos. Sci., NC State Univ., Raleigh, NC Carey J. Jang and Sharon Phillips Office of Air Quality Planning and Standards, the U.S. EPA, Research Triangle Park, NC Presentation at the 7th Annual CMAS Conference, Chapel Hill, NC, October 6-8, 2008

  2. Presentation Outline • Introduction • Case Studies • Intercontinental Transport over Trans-Pacific • Horizontal Flux Analysis • Process Analysis • Impact of Asian Anthropogenic Emissions on US Air Quality • Regional Climate-Air Quality Interactions over East Asia • Direct Feedbacks • Semi-direct Feedbacks • Indirect Feedbacks • Summary

  3. Tropopause Mixing Free troposphere 2 km “Direct” intercontinental transport Boundary layer lifting subsidence Asia N. America Europe Mechanismsfor Intercontinental Transport Between Northern Midlatitude Continents boundary layer advection Intercontinental Transport: uplifting of PM to troposphere/subtropical jet stream Source: Jacob et al., 2004

  4. Intercontinental Transport over Trans-Pacific • Modeling Tool • U.S. EPA’s Models-3/Community Multiscale Air Quality (CMAQ) modeling system version 4.4 • 180×74 horizontal grid cells with 108-km horizontal grid spacing • 16 layers (surface to ~16 km) • Meteorology • Mesoscale Model MM5 (V3.6) • IC/BC • GEOS-CHEM • Emission Inventory • -- North America • U.S.: NEI (1999) Projected to 2001 & Biogenic EI System BEIS-3 • Canada: 1995 EI & BEIS-3 • Mexico: 1999 Big Bend Regional Aerosol and Visibility Observational (BRAVO)Study & BEIS-3 • -- Asia/China • Transport and Chemical Evolution over the Pacific (TRACE-P) and Aerosol Characterization Experiment over Asia (ACE-Asia) 2000 EI • Simulations • Baseline with PA: 01, 04, 07, and 10 in 2001 • Sensitivity: zero Asian man-made emissions • Measurements • Surface: • Met: NCDC, CASTNET, STN, SEARCH, NADP • Chem: Japan, China, main US networks • Satellite: NO2 (GOME), CO (MOPITT), • TOMS/SBUV TOR, AOD (MODIS)

  5. Performance Statistics (NMB, %) for Surface Predictions U.S. China Japan

  6. Evaluation of Column Predictions NO2 TOR AOD Obs Sim Performance Statistics (NMB, %)

  7. Layer 1 (surface) Layer 12 (~5 km) Horizontal Fluxes of Gaseous Species (mg m-2s-1) O3 NOx PAN HCHO 3.1 m/s 8.4 m/s

  8. Horizontal Fluxes of PM Species (mg m-2s-1) Layer 1 (surface) Layer 12 (~5 km) PM2.5 SO42- NO3- OC 3.1 m/s 8.4 m/s

  9. X-Z Cross-Sections between 25-50 °N of Horizontal Fluxes of Gas/PM2.5 Species (mg m-2s-1) Gases PM O3 PM2.5 NOx SO42- PAN NO3- HCHO OC

  10. Process Analysis-IPR, April, 2001 O3 (Gmoles/day) PM2.5 (Ggrams/day) East Asia Pacific Ocean U.S.

  11. Total Air Pollution Export From Asia and Into U.S. 1TotalExport_Asia-total export out of the PBL over Eastern Asia; TotalExport_US-total export out of the PBL over the U.S. 2 Difference-net export/import due to the Asia anthropogenic emissions.

  12. Enhancement of Gas and PM2.5 species in April 2001 due to Asian Anthropogenic Emissions in the West (Red) and East (Blue) U.S.

  13. MM5/CMAQ vs. WRF/Chem and Aerosol Feedbacks over China • Period:1-31 Jan./Jul. 2005 • Domain: 164 × 97 grid cells • Horizontal resolution: 36 km • Vertical resolution: • 30 layers (up to 50 mb) • Emissions: • U.S. EPA SED-JES • Sea salt: online calculation • Meteorology IC and BC: • NCEP/NCAR Global Reanalysis • Chemical IC and BC: • CMAQ • Gas-phase chemistry: • CBM-Z • Aerosol module: • MOSAIC • Cloud chemistry module: • CMU • Scenarios: • Met; Met+Gas; Met+Gas+PM+Cld. Aq. • Data for model evaluation: • China/NCDC: T, RH, WS, Precip, PM, API • Japan (2078 sites):T, RH, WS, SO2, NO2, CO, O3, PM • China (a few sites):PM2.5 and Air pollution indices • MOPITT: CO • OMI: NO2 • TOMS: Tropospheric Ozone Residual (TOR) • MODIS: AOD

  14. Aerosol Direct Effects on Shortwave Radiation and Photolysis Direct Effects on Shortwave Radiation Direct Effects on NO2 Photolysis Absolute Difference PM2.5 Mass Jan Jul PM2.5 decreases shortwave radiation and NO2 photolysis over most East Asia in Jan/Jul

  15. Aerosol Semi-Direct Effects on PBL Meteorology 2-m Temperature PBL Height PM2.5 Mass Absolute Difference Jan Jul PM2.5 slightly decreases 2-m temperature; PM2.5 decreases PBL height in larger area in Jul than in Jan

  16. Aerosol Indirect Effects on CCN and Precipitation PM2.5 Mass CCN (S = 1%) Changes in Precipitation Jan Jul Higher CCN concentrations over larger areas in East Asia in Jan Dominancy of suppression of precipitation in East Asia in Jul

  17. Summary • Major Trans-Pacific Transport Mechanisms • Strongest export for O3, PAN, HCHO, and NO3- at 25-45º N in the LFT • Strong export for CO, O3, PM2.5, SO42- at the mid-latitude in the PBL • Relative Importance of Atmospheric Processes • Transport, chemistry, and dry depo are important for O3 • Emissions, aerosol/cloud proc., and transport are important for PM2.5 • Impact of Asian Anthropogenic Emissions on US AQ • Total export: 0.1 Gmoles/day of O3 and 0.5 Ggrams/day of PM2.5 • Increases background O3 in the WUS by ~1 ppb (~2.5%) in monthly average, and up to 2.5 ppb in daily average • Increases background SO42- in the WUS by 0.4 mg m-3 (~20%) in monthly average, and up to 1.0 mg m-3 in daily average • Aerosol Feedbacks to Regional Climate • PM2.5 decreases shortwave radiation and NO2 photolysis • PM2.5 decreases 2-m temperature and PBL height • PM2.5 enhances CCN formation and suppresses precipitation

  18. Acknowledgements • U.S. Environmental Protection Agency (EPA)’s ICAP Project, • NASA Award No. NNG04GJ90G and NSF Career award at NCSU • Andreas Richter, the University of Bremen, Germany, for • providing GOME NO2 data; Hilary E. Snell, AER Inc., for • processing MOPITT CO and GOME NO2; Jack Fishman and John • K. Creilson, NASA Langley Research Center, for providing TOR • Alice Gilliland and Steve Howard, U.S. EPA, for providing • observational data from national networks over U.S. and the • Fortran code for extracting data from observations and CMAQ; • Shaocai Yu, U.S. EPA, for providing Fortran code for • statistical calculations • Jiming Hao and Ke-Bin He, Tsinghua University, China, for • providing the observational data in Beijing, China • Takigawa Masayuki, the Frontier Research Center for Global • Change, Japan, for providing the codes for the extraction of • Japan data

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