Improved OMPS Nadir Profiler Straylight Characterization and correction for NOAA-21

There are three Ozone Mapping and Profiler Suite (OMPS) instruments onboard NOAA Joint Polar Satellite System (JPSS) satellites, providing critical Earth observations for near real time EDR retrieval, such as ozone. The quality of retrieved ozone depends on the radiometric quality of the OMPS SDR data. Among several calibration parameters being used to convert OMPS raw data to SDR data, Straylight is an important calibration parameter for maintaining the accuracy of OMPS data, for applications requiring precise measurements of atmospheric parameters such as ozone concentrations. SL contamination in the observed radiance is a common issue among Earth observing satellite instruments. If not corrected properly, the SL could lead to an error of several percent of the observed radiance. This study focuses on the straylight characterization and correction of OMPS Nadir Profiler (NP) sensor onboard NOAA-21. This study shows how the newly developed SL correction performs better than the at-launch operational SL correction, with accuracy improved by more than 2% at 273 nm. In addition, the new SL correction significantly reduced the latitude dependency of the radiance data quality, resulting in the improved radiometric consistency with the SNPP and the NOAA-20 OMPS NP. After comparing the performance of all three NP SL corrections, it was observed that the NOAA-21 indicated better performance than the other two sensors. The SL performance is validated through intercomparison and through correlations with longer wavelengths. In addition to the straylight characterization, this study will explore the NOAA-21 SL correction using machine learning.