Stray Light Calculation and Validation of Ozone Mapping and Profiler Suite Limb Profiler and Nadir Sensors

The Ozone Mapper and Profiler Suite (OMPS) on the Suomi NPP (launched 2011) and NOAA-20 (launched 2017) satellites consist of three instruments: Limb Profiler (LP), Nadir Mapper (NM) and Nadir Profiler (NP). These instruments measure ozone and other atmospheric constituents using wide-field telescopes and spectral-spatial CCD detectors. The JPSS-2 OMPS is scheduled to launch in 2021. Stray light from outside the spectral band has always affected the data quality of these instruments, but the introduction of 2D detectors has added the spatial component to stray light. Stray light is removed from atmosphere measurements via matrix deconvolution of the instrument point spread function (PSF), which is measured on the ground. In this presentation we will discuss the methods being used to identify and eliminate residual errors after the initial stray light correction. We begin with a brief description of the PSF characterizations, followed by an explanation of how their application to the data fails to remove all sources of stray light. Some of the "missing" stray light in the Limb instrument was only identified through special engineering tests on the JPSS-2 model. We will show our progress accounting for this additional stray light in the Earth data of the Suomi NPP instrument. Likewise, the Nadir Mapper has a poorly characterized source of stray light that contributes unwanted signal near 300 nm. After trying multiple techniques to identify and remove this stray light we have found that comparing radiances from the two Nadir sensors in their spectral overlap region is the most effective.