1Dept. of Environmental Science and Engineering, Gwangju Inst. of Science and Technology (GIST), Gwangju, Korea, and also at Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Inst. of Science and Technology (GIST), Gwangju, Korea
2Hazardous Substance Research Center, Korea Inst. of Science and Technology (KIST), Seoul, Korea
3Earth System Science Interdisciplinary Center (ESSIC), Univ. of Maryland, MD 20742, USA
4Dept. of Atmospheric Science, Yonsei Univ., Seoul, Korea
5Dept. of Environmental Science, Hankuk Univ. of Foreign Studies, Yongin-si, Gyeonggi-do, Korea
Abstract. In this study, the spatio-temporal and seasonal distributions of EOS/Terra Moderate Resolution Imaging Spectroradiometer (MODIS)-derived aerosol optical depth (AOD) over East Asia were analyzed in conjunction with US EPA Models-3/CMAQ v4.3 modeling. In this study, two MODIS AOD products (τ MODIS:τM-BAER and τNASA) retrieved through a modified Bremen Aerosol Retrieval (M-BAER) algorithm and NASA collection 5 (C005) algorithm were compared with the AOD (τCMAQ) that was calculated from the US EPA Models-3/CMAQ model simulations. In general, the CMAQ-predicted AOD values captured the spatial and temporal variations of the two MODIS AOD products over East Asia reasonable well. Since τMODIS cannot provide information on the aerosol chemical composition in the atmosphere, different aerosol formation characteristics in different regions and different seasons in East Asia cannot be described or identified by τMODIS itself. Therefore, the seasonally and regionally varying aerosol formation and distribution characteristics were investigated by the US EPA Models-3/CMAQ v4.3 model simulations. The contribution of each particulate chemical species to τM-BAER, τNASA, and τCMAQ showed strong spatial, temporal and seasonal variations. For example, during the summer episode, τM-BAER, τNASA, and τCMAQ were mainly raised due to high concentrations of (NH4)2SO4 over Chinese urban and industrial centers and secondary organic aerosols (SOAs) over the southern parts of China, whereas during the winter episode, τM-BAER, τNASA, and τCMAQ were higher due largely to high levels of NH3NO3 formed over the urban and industrial centers, as well as in areas with high NH3 emissions. In addition, the accuracy of τM-BAER and τNASA was evaluated by a comparison with the AOD (τAERONET) from the AERONET sites in East Asia. Both τM-BAER and τNASA showed a strong correlation with τAERONETR around the 1:1 line (R=0.79), indicating promising potential for the application of both the M-BAER and NASA aerosol retrieval algorithms to satellite-based air quality monitoring studies in East Asia.