Aerosol retrieval and atmospheric correction of HJ-1 CCD data over Beijing

摘要

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.