Radiometric cross-calibration of CBERS-02 IRMSS thermal channel against TERRA MODIS

Abstract

TERRA MODIS band 31 was selected as the criterion for doing the radiometric cross-calibration of CBERS-02 IRMSS band 9 in this paper. From August to December, 2004, seven times day and night synchronous images of two sensors passing through the Lake Qinghai and Lake Taihu were selected to get the cross-calibration data. Using TERRA MODIS band 31 data to conduct out the at pupil radiance of CBERS-02 IRMSS band 9 based on the two sensors' spectrum matching, and then pick-up the DN values from the IRMSS data in the same area. A new model to calculate the radiometric calibration coefficients was carried out in this paper: multi-points linear regression method with 7 times day and night synchronous images at different dates and locations. This new method can obviously control the radiometric calibration uncertainties aroused by the single point method to do the in-flight calibration like CBERS-02 IRMSS, this kind of sensors can't collect the radiometric signals from the deep space. In this research, the radiometric calibration coefficients obtained through the linear regression method were 8.0567 (gain, unit: DN/ (W/m2/sr1/μm1)) and 47.892 (offset, unit: DN). Preliminary estimate of calibration coefficients using Shanghai area was carried out and the results showed that the calibration coefficients obtained from the linear regression method was with a similar precision to TERRA MODIS band 31's. This suit of calibration coefficients can satisfy the quantitative applications of CBERS-02 IRMSS thermal data.