Published on October 16, 2007
Slide1: Hong Liao Institute of Atmospheric Physics Chinese Academy of Sciences Simulation of Air Pollutants (AP) over China using the GEOS-CHEM What do we know about AP over China?: What do we know about AP over China? Column burden of tropospheric NO2 over 1996-2006 ( 1015 molecules cm-2) GOME NO2 Measurements Four heavily polluted areas: Northern China， Yangtze Delta, Sichuan Basin, and Pearl River Delta High concentrations: PM2.5 concentrations are about 10-15 times the US Values! Slide3: What don’t we know about AP over China? Seasonal variation Previous modeling and measurements mostly focused on a short period of time and a specific location Chemical composition of aerosols Few sites with long-term speciated measurements Slide4: Ground Measurements of Ozone in China Slide5: MISR Aerosol Optical Depth (June-August ) Aerosols over Beijing Ground measurements at Beijing for 2001 AERONET AODs at Beijing (averaged over 2001-2005) Slide6: Ground Measurements of OC Slide7: Annual Average Conc. of PM2.5 at Beijing in year 2000: 95.5 (μg m-3 ) OC Accounts for a Large Fraction of PM2.5 Zhang et al., 2002 Slide8: Ground Measurements of Sulfate Slide9: GEOS-Chem Simulation over China (GEOS-3 met fields, default emissions) Slide10: GEOS-Chem Prediction of Sulfate The GEOS-Chem captures qualitatively the maximum concentrations in winter, but predicted concentrations have a low bias throughout the year. Predicted distribution of maximum concentrations does not match well with that observed by satellites. January July (μg m-3) Slide11: GEOS-Chem Prediction of Nitrate and Ammonium (January) (July) (μg m-3) (January) (July) Slide12: GEOS-Chem Prediction of Carbonaceous Aerosols Carbonaceous aerosol concentrations are too low as compared with ground measurements! BC (January) BC (July) OC (January) OC (July) (μg m-3) Slide13: GEOS-Chem Prediction of PM2.5 Concentrations Concentrations are not as high as ground measurements, especially in summer. January July (μg m-3) Slide14: Plans to Improve the GEOS-Chem Simulation over China Update emission inventories Simulation with David Streets’ year 2000 emission inventories produces better distribution of air pollutants but lower concentrations than that with default emissions. Constrain sulfur emissions by ground measurements of SO2 China has long-term measurements of SO2 at many locations. Constrain emissions of NOx, VOCs, and CO by satellite measurements Ways to constrain BC and OC emissions? Suggestions are welcome! Slide15: Compare GEOS-Chem Simulated AODs with Measurements From Chinese Sun Hazemeter Network Xin et al., JGR, 2007 Slide16: Ongoing Research Improve and evaluate simulation of AP over China Better understanding of intercontinental transport More accurate boundary conditions for regional air quality modeling Examine how Asian monsoon influences AP Slide17: Near Future Application of the GEOS-Chem To understand the general characteristics of AP over whole China domain (GEOS-Chem) Geographical distribution and seasonal variation; Chemical composition. Simulation of severe pollution episodes (GEOS-Chem/MM5/CMAQ) Forecast of severe pollution events (GEOS-Chem/MM5/CMAQ) Assessment of future changes of Asian pollutants Short term (5-10 years) (GEOS-Chem/MM5/CMAQ) Long term (50 years) (GCM/MM5/CMAQ) Slide18: The End Thank you!