[Variations in Aerosol Optical Depth over Three Northeastern Provinces of China, in 2003-2014]

Based on the MODIS-Aqua aerosol optical depth (AOD) products from 2003 to 2014, Nighttime Lights Time data from DMSP satellites and basic meteorological data, the AOD spatial distributions of interannual and seasonal variations over three northeastern provinces of China(Liaoning, Jilin, Heilongjiang) were analyzed. It was found that there was a northeast-southwest area of high annual average AOD composed of Dalian, Shenyang, Changchun, Harbin and other cities, the 12-year average AOD value was 0.4-0.8. The low AOD occurred in the eastern and northern areas of the three northeastern provinces of China, where the forest-covering rate was high, and the 12-year average AOD value was less than 0.3. The seasonal variations of annual average AOD showed an increasing trend from spring to summer, then decreased in autumn and increased again in winter. The interannual variations of AOD over three northeastern provinces of China showed a decreasing trend in most areas, but the increasing trend occurred in the northeast-southwest region with the axis formed by Shenyang, Changchun and Harbin, revealing the polarization in recent 10 years over three northeastern provinces of China. In addition, spatial distribution of annual average AOD over three northeastern provinces of China in the years of strong and weak Western North Pacific Summer Monsoon was studied. Affected by the surface wind field, annual average AOD in weak monsoon years was higher than that in strong monsoon years.