Aerosol retrieval and atmospheric correction of HJ-1 CCD data over Beijing
北京地区HJ-1卫星CCD数据的气溶胶反演及在大气校正中的应用

Compared to moderate/low resolution satellite sensors for aerosol detection, the high spatial resolution of HJ-1 CCD camera (30 m) provides an opportunity to easily find spectrally pure pixels (SPP) over urban areas. In this study, we developed an SPP algorithm for urban Aerosol Optical Depth (AOD) retrieval using HJ-1 CCD data. Pixel Purity Index (PPI) is used to identify the pure pixels in the image. The surface reflectances of the pure pixels were estimated from the multi-temporal CCD measurements of HJ-1A and HJ-1B based on the surface Bi-directional Reflectance Distribution Function (BRDF) model. Then the AOD can be retrieved from satellite measurements. The comparison with ground-based AErosol RObotic NETwork AERONET AOD measurements shows good performance of our algorithm. A significant correlation coefficient with R=0.83 was obtained with a linear regression slope close to 1 and a intercept of 0.053. With the retrieved AOD as an input, HJ-1CCD data over urban areas was significantly improved after the atmospheric correction.