Retrieval of aerosol optical depth over the Yangtze River Delta with HJ-1 data

Aerosol optical depth (AOD) is a key indicator of atmospheric environment. Aerosol remote sensing is the most efficient way to obtain the temporal and spatial distributions of AOD. In this paper, the data from Environment Satellite (HJ-1) CCD camera were employed to retrieve AOD by using deep blue algorithm over the Yangtze River Delta. The third band (in blue) was firstly extracted from the MODIS land surface reflectance product (MOD09) and then converted to the first band of CCD/HJ-1. According to the characteristics of the study area and CCD data, a multi-dimension look up table was then built by the Second Simulation of the Satellite Signal in the Solar Spectrum (6S). AOD over the Yangtze River Delta were finally retrieved from the radiance of the first band of CCD/HJ-1. After the retrieved AOD were validated by the MODIS AOD product (MOD04), the correlation coefficient (R) is 0.64 by regression of all cloud screened pixels (1147). The retrieved AOD has a higher spatial resolution than the MODIS AOD and thus can provide more detailed information. Compared with the AERONET ground observation data, the retrieved AOD is closer to the ground-based data than the MODIS AOD.