Comparison of different calibration algorithms for the medium resolution spectral imager in infrared band

Abstract

As a key payload on the Fengyun-3C (FY-3C) polarorbit meteorological satellite, the medium resolution spectral imager (MERSI) is installed to provide the global coverage of top-of-atmosphere radiances. In order to ensure the on-orbit radiometric data quality of the MERSI, the modified calibration equation for the thermal infrared channel can be obtained by the blackbody (BB) and deep space view (SV). Different calibration algorithms are investigated to obtain the time series of the calibration coefficients a 0, a 1 and a 2, and the accuracy of the radiometric calibration is evaluated by comparing the BB irradiance calculated by those calibration coefficients and the standard BB irradiance, whose irradiance differences are within the order of 10−4 W/m2/μm/sr. Moreover, the differences of the BB inversed and equivalent temperatures by different algorithms show a similar behavior, whose values changing from 0.26 K to 0.28 K. These works provide important information for tracking the instrument performance along with the quantitative remote sensing application.