Terrestrial aerosol retrieval over Beijing from Chinese GF-1 data based on the blue/red correlation.

Abstract

Wide field imager (WFV) cameras are Chinese high-resolution optical sensors in the GF-1 satellite, and the data from WFV cameras have been applied to environmental monitoring. In this paper, for wide swath observation of WFV, the blue/red correlation is more suitable for retrieving Aerosol Optical Depth (AOD). the blue/red correlation of surface reflectance was analysed by Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance products for each pixel over the Beijing area. A significant linear relationship was found between red and blue bands in most of the area, corresponding to urban, farmland, forest, and water areas. Assisted by geographic blue/red correlation, the aerosol inversion method for WFV data was developed. After selecting the data between July 2016 and August 2017, the AOD was obtained using our method and was compared with the ground results from three Aerosol Robotic Network (AERONET) Beijing sites. The results showed that the correlation coefficient between the AOD of our method and that of the ground measurements was about 0.9, and approximately 53% of the points were within the expected error (0.05 ± 0.20τ), and the results are better than MODIS 10 km aerosol product.