Decadal climatological trends of aerosol optical parameters over three different environments in South Korea

摘要

Decadal climatology of aerosol optical parameters derived from Moderate Resolution Imaging Spectroradiometer (MODIS) on board Terra satellite has been analysed during past decade (February 2000 to February 2010) over three different environments in South Korea. Seoul, a continental urban station showed a significant decadal decrease of around 22% in aerosol optical depth (AOD) at 550 nm during observational period. The corresponding decrease in AOD found to be 18.7% over Busan, a coastal station. However Jeju, a volcanically sedimented island station in Korea showed negligible changes in AOD (1.4%). Fine mode fraction (FMF) and Angstrom exponent (ANG) parameters also showed a significant decadal reduction, indicating the decrease in fine mode aerosols, which are majorly produced due to anthropogenic activities in land areas. On analysing the decadal trends in seasonal climatology, it is found that aerosol parameters in general were showing a decreasing trend in different seasons except during spring. The decadal trend in meteorological parameters did not show a perfect alignment with aerosol trends. This suggests that the decadal decrease in aerosols could be mainly attributed to reduction in anthropogenic aerosol emissions. The surface temperature over the stations showed a significant increase of 8% to 11%. This study suggests that, in spite of positive effects in pollution perspective, the reduced AOD may in part contribute the increasing trend of surface temperature.