Long Time Series Radiometric Calibration of Suomi-NPP VIIRS Based on Surface Hyperspectral BRDF Model

In order to improve the calibration frequency of optical satellite remote sensors, a high-frequency absolute radiometric calibration method based on the surface hyperspectral bidirectional reflectance distribution function (BRDF) model is proposed, and the long time series absolute radiometric calibration of Suomi-national polar orbiting partnership spacecraft (Suomi-NPP) visible infrared imaging radiometer suite(VIIRS)is realized. The principle of the absolute radiometric calibration method based on the surface hyperspectral BRDF model is introduced. In April 2018 and August 2018, the surface directional reflectance of the Dunhuang test site was measured by the hyperspectral BRDF manual measurement system, and the hyperspectral BRDF model parameters of the Dunhuang site were inversed based on the semi-empirical kernel-driven model. Based on the BRDF models the apparent reflectance of VIIRS M1-M11 bands in the whole year of 2018 was calculated, and compared with the satellite-observed ones. The results show that the effective calibration number of Suomi NPP VIIRS is 51 in 2018 the relative deviation of model-calculated apparent reflectance and satellite-observed ones of the M1-M7 bands is less than 3.23%The proposed method can effectively improve the calibration frequency of satellite and track the change of radiometric characteristics of the load in time.