WRF-Chem Simulation of Air Quality in China: Sensitivity Analyses of PM Concentrations to Emissions, Atmospheric Transport, and Secondary Organic Aerosol Formation

Monday, 15 December 2014
Min Zhong1, Eri Saikawa1, Vaishali Naik2,3, Larry Wayne Horowitz2,4, Masayuki Takigawa5 and Yu Zhao6, (1)Emory University, Atlanta, GA, United States, (2)Geophysical Fluid Dynamics Laboratory, Princeton, NJ, United States, (3)University Corporation for Atmospheric Research, Boulder, CO, United States, (4)Princeton Univ, Princeton, NJ, United States, (5)JAMSTEC, Yokohama, Japan, (6)Nanjing University, Nanjing, China
We investigate air quality in China in April 2007, using the Weather Research and Forecasting model coupled with Chemistry version 3.5 (WRF-Chem) at a spatial resolution of 20km × 20km with 31 vertical levels. The model domain covers the entire East Asian region with 399 × 299 grid cells. The initial and lateral chemical boundary conditions are taken from a present-day simulation of the NOAA Geophysical Fluid Dynamics Laboratory (GFDL) global chemistry-climate model AM3. The Regional Acid Deposition version 2 (RADM2) atmospheric chemical mechanism is used for gas-phase chemistry and the Model Aerosol Dynamics for Europe with the Secondary Organic Aerosol Model (MADE/SORGAM) and aqueous chemistry is used for aerosol chemistry. The emissions of gaseous pollutants (CO, NOx, NH3, VOCs, and SO2) and particulate matter (BC, OC, PM2.5, and PM10) are taken from the Regional Emission Inventory in Asia (REAS) version 2. Dust and sea salt emissions are simulated online, where dust parameters are optimized using observed particular matter (PM10) concentrations in 73 cities in China. We add gravitational settlement for dust and sea salt in vertical levels. The preliminary results show that the model predicts PM10 reasonably well compared to the ground measurement data. The bias in modeled PM10 concentrations in South and Northwest­­­­­­­ China is less than 10%. We will present results of sensitivity analyses that assess the impact of emissions, atmospheric transport, and secondary organic aerosol formation on PM concentrations.