An Analysis of MODIS Aerosol Optical Properties and Ground-based Mass Concentrations in Central Korea in 2009

Abstract

Satellite-retrieved data on Aerosol Optical Depth (AOD) and Ångström exponent (AE) using a Moderate Resolution Imaging Spectrometer (MODIS) were used to analyze large-scale distributions of atmospheric aerosols in East Asia. AOD was relatively high in March (0.44±0.25) and low in September (0.24±0.21) in the East Asian region in 2009. Sandstorms originating from the deserts and dry areas in Northern China and Mongolia were transported on a massive scale during the springtime, thus contributing to the high AOD in East Asia. Although PM10 with diameters ≤10 µm was the highest in February at Anmyon, Cheongwon and Ulleung, which is located leeward about half-way through the Korean Peninsula, AOD rose to a high in May. The growth of hygroscopic aerosols moving with increases in relative humidity prior to the Asian monsoon season contributed to a high AOD level in May. AE typically reaches its highest value (1.30±0.37) in August due to anthropogenic aerosols originating from industrial areas in Eastern China, while AOD stays low in summer due to the removal process caused by rainfall. The linear correlation coefficients of the MODIS AOD and ground-based mass concentrations of PM10 at Anmyon, Cheongwon and Ulleung were 0.4-0.6. Four cases (six days) of mineral dustfall from sandstorms and six cases (twelve days) of anthropogenically polluted particles were observed in the central area of the Korean Peninsula in 2009. PM10 mass concentrations increased at both Anmyon and Cheongwon in the cases of mineral dustfall and anthropogenically polluted particles. Cases of dustfall from sandstorms and anthropogenic polluted particles, with increasing PM10 mass concentrations, exhibited higher AOD values in the Yellow Sea region.