Information Acquisition Of Aerosol Optical Depth From MODIS Sensor And Application Study In Bohai Rim

Aerosols are major players in Earth's climate, radiation budget, cloud processes and air quality.?Aerosol is a multi-phase system composed of a suspension of fine solid particles or liquid droplets in a gas and carrier gas,and it is one of the most important components. Aerosols are known to have an impact radiation balance on earth-atmosphere system by means of scattering or absorption of solar radiation,so aerosol is the most important factor in climate change research and plays a vital important role in human health. Aerosol optical depth(AOD) is the most important parameter of aerosol, and it is an important physical quantity to show atmospheric turbidity, a vital factor to confirm climatic effects of aerosol, and it also has a close relation between climate change and human activity. In the current environment, Bohai Rim is one of three major urban agglomeration regions with highly developing economy following the Yangtze Delta region and Pearl River Delta, the study of atmosphere aerosol optical characteristics over this region is important for understanding the environment and climate simulation in Bohai Rim and East China.In this paper, firstly, some different algorithm of retrieving aerosol optical depth had been introduced. These algorithms include dense dark vegetation, the comparison method. Base on these works, aerosol product data of the years from 2001 to 2009 published by NASA were used to analyze the temporal change and spatial distribution of aerosol optical depth in Bohai Rim on the base of precision evaluation. And some factors that influence the aerosol optical depth effect were analyzed.?The results have shown that spatial distribution of aerosol optical depth has a distinct regional characteristic. The spatial distribution is characterized that the much high value of aerosol optical depth was south-central area in Liaoning Province, south-central area in Hebei Province, Southeast area in Beijing city, Tianjin city than other regions in Bohai Rim, and some other congested downtown areas; On the country, the low value of aerosol optical depth data was in some mountainous regions with higher percentage of forest cover such as Changbai Mountain, Taihang Mountain and so on. In terms of time, AOD value shows some kind of fluctuation in the region. The value of AOD was the smallest in 2003 and the most in 2009. In terms of seasonal change, AOD value was the highest in summer, and was 0.62; spring is the next season and AOD value was 0.58; then autumn, the value was 0.36; and the last was winter, the value is 0.27. The trend from the months, the peak AOD reaches Bohai Rim in June, and the lowest value appears in?December.Base on these works, we analyze the connection between aerosol optical depth and Land-Use and Land-Cover Change (LUCC), Digital Elevation Model (DEM)and so on. There are significant negative correlations between the AOD and elevation. the height of the surface has high AOD value than the low. Forests and grasslands were the low AOD, but agricultural land and urban present a high AOD. These results provide important basic data for climate research and environment research.