Long-Term Assessment of Inter-Sensor Radiometric Biases Among SNPP, NOAA-20, NOAA-21 OMPS Nadir and CrIS Instruments Using the NOAA ICVS Framework

This study presents a long-term assessment of inter-sensor radiometric calibration biases for NOAA OMPS nadir and CrIS instruments using four well-established validation methodologies implemented through the Inter-Sensor Radiometric Bias Assessment (iSensor-RCBA) portal, a component of the STAR Integrated Calibration/Validation System (ICVS) monitoring system. Four validation methods include the 32-Day Average, CRTM-DD, SNO, and Sensor-DD via SNO—to enhance monitoring and detect radiometric errors. The results demonstrate that the SDR data quality from three OMPS nadir instruments and three CrIS instruments aboard the SNPP, NOAA-20, and NOAA-21 satellites has generally remained stable over the long term, meeting scientific requirements with some margin—mainly during early orbit phases, anomalies, malfunctions, or calibration updates. Among four methodologies, the 32-Day method excels in identifying limitations of other used validation methods, particularly in terms of inter-sensor bias geographical coverage. For instance, the 32-Day method identifies an unusual feature in the NOAA-21 CrIS SDR data over the high latitudes of the Southern Hemisphere during the spring and summer seasons, which was not detected using the other three methods due to a limited coverage. The SNO method is particularly effective for detecting long-term calibration discrepancies in a single instrument. This is illustrated by an approximately 10-year time series of inter-sensor bias between SNPP OMPS Nadir Mapper and Metop-B GOME-2, which reveals significant degradation in GOME-2. Using the SNO method, two significant geolocation problems occurred on SNPP spacecraft were captured in inter-sensor biases between SNPP CrIS and GOES-16 ABI. Therefore, the iSensor-RCBA portal can serve as a crucial tool for providing supplemental information about long-term radiometric calibration stability of satellite radiance data across JPSS and other satellite instruments.