Inversion Of Aerosol Optical Depth Based On The Multi-source Satellite Remote Sensing Over Chengdu Region In Sichuan Province

This paper was completed under the project: Air Pollution Prevention and Control Countermeasures of Sichuan and Chengdu Region(Project number: 2013HBZX03). This paper performed the retrieval of aerosol optical depth(AOD) based on the MODIS(Moderate-resolution Imaging Spectroradiometer) data and the extended dark target method was used in this study. Also the analysis of the spatial-temporal of AOD over Chengdu region in Sichuan was completed. To perform a high-resolution aerosol optical depth(AOD) inversion from the HJ-1 satellites, a dark pixel algorithm utilizing the HJ-1 satellite data was developed based on the MODIS algorithm. The summarizes of the primary coverage of this study as follows to show:(1) The result of AOD of Chengdu region was performed based on the extended dark target method of MODIS data, which has a spatial resolution of 1KM. The AOD result over year 2008 to year 2012 in 13 counties in Chengdu region shows that, the AOD of Chengdu region raise from year 2008 to year 2011 and it got the max AOD value in year 2011. Compared with year 2011, the AOD of year 2012 got a slight decline. Xindu, Shuangliu, Xinjin and Downtown Chengdu are the AODmaximum areas in the 13 counties, the value range of AOD in these areas is 0.921-0.932. The AOD of the 13 counties got the maximum in March and the minimum in October. To compare with the result of MOD04 product, the relative difference is 16.46% and the result has the credibility.(2) By analyzing the relationship between the apparent reflectance from the 1.65 μm and 2.1 μm channels of MODIS, a method for estimating albedo using the 1.65 μm channel data of the HJ-1 satellites was established, and a high-resolution AOD retrieval in the Chengdu region based on the HJ-1 satellite was completed. A comparison of the inversion results with MOD04 data produced a correlation of 0.932, respectively, with an absolute difference of 0.084. A comparison of theinversion results with CE318 measured data produced a correlation of 0.957, respectively, with an absolute error of 0.106.(3) The retrieval error caused by the albedo and aerosol model was analyzed. An analysis of the AOD retrieval error caused by the albedo showed that the AOD retrieval error and the albedo error has a linear relationship. The high AOD areas are not sensitive to the albedo error. An analysis of the AOD retrieval results from different aerosol models showed that the rural aerosol model was suitable as a general model for establishing an aerosol inversion look-up table for the Chengdu region.