Preliminary validation of GF-1/GF-2 surface reflectance products over land using VNIR atmospheric correction method

The surface reflectance is an essential parameter for the quantitative applications using remote sensing satellite data; therefore, it is of great importance for the scientific community to produce standard surface reflectance products using an operational running algorithm and system. There have been various medium- to high-resolution satellites in China, yet there is still a lack of relevant surface reflectance products and systems. In this paper, high-resolution GF-1/GF-2 data from the year 2014 and 2017 were utilized for retrieval of surface reflectance products over land by using an operational atmospheric correction algorithm, adaptive to most multispectral satellites with visible and near-infrared bands (VNIR), namely, the VNIR approach. This method was based on the Second Simulation of a Satellite Signal in the Solar Spectrum, Vector (6SV) code and the look-up tables (LUTs). The surface reflectance products over land were validated against the ground-based atmospherically corrected reflectance over Beijing-Tianjin-Hebei regions and middle and lower regions of the Yangtze River in China. The preliminary validation results showed that the surface reflectance products agreed quiet well with the ground-based corrected reflectance, with the linear regression fitting coefficients being 1.09– 1.03, the correlation coefficients of R2 being 0.97–0.99, and the Root Mean Square Error (RMSE) being 0.01. Simultaneously, the mean reflectance normalized residuals between the surface reflectance products and the ground-based corrected reflectance were 19.7 %, 13.5 %, 8.7 %, and 6.6 %, respectively, indicating that the surface reflectance products over land derived from VNIR atmospheric correction approach had a good accuracy.