GEO-GEO Intercomparison as a Tool for Instrument Characterization

Geostationary satellites inter-comparison (GEO-GEO) can play an important role to characterize the calibration difference between two satellites, as well as sensor radiometric validation and monitoring for calibration stability. It can also display sensor performance regarding relative calibration accuracy variation by comparing with relatively well calibrated and controlled sensor. In this study, we will compare the radiometric calibration difference for the infrared (IR) bands among Himawari 8 Advanced Himawari Imager (AHI), GOES-16 Advanced Baseline Imager (ABI), GOES-17 ABI, and GEO-Korea Multi-Purpose Satellite-2 (GK-2A) Advanced Meteorological Imager (AMI) using GEO-GEO inter-comparison method. The collocation criteria should be considered for the same geolocation, similar viewing zenith angle difference and almost the same observation time between two satellites. The target selection and analysis method for GEO-GEO inter-comparison can be conducted in several different ways to avoid surface changes of the target and parallax effects. In this study, pixel to pixel matched method over the stable target surface will be used. Findings are expected to help improve current calibration issues of several different geostationary satellites by comparing in multiple ways directly or indirectly. Results will be presented in the coming meeting.