The shortwave infrared (SWIR) bands (1.64 and 2.13µm) of FY-3A MERSI have multiple electronic gains. Unfortunately, the SWIR bands are influenced by anomaly electronic gain jumps possibly induced by space environment, which restricts the data application. In this paper, the long-term data series of space view (SV) observation and sensor temperature measurement of FY-3A MERSI are used to analyze the on-orbit variation of SWIR band gains, and a gain level auto identification algorithm is presented. Based on it, the SV data are normalized to the same gain level with good results. Besides, the long-term drifting of SV is revealed, as well as the temperature dependent feature of the radiometric response of 2.13 µm band, and a preliminary temperature correction model is obtained. Based on this research, continuous on-orbit radiometric calibration can be implemented and the application ability of the SWIR data could be recovered. The revealed features of SV long-term drifting and temperature dependency provide valuable information for the Chinese sensor design, manufacture and testing, as well as elaborated on-orbit radiometric calibration processing.
['Ling Sun']
On-orbit gain level identification and normalization of FY-3A mersi shortwave infrared bands based on space view observation