Potential Gaps in the Satellite Observing System Coverage: Assessment of Impact on NOAA's Numerical Weather Prediction Overall Skills Monthly Weather Review

The current constellation of environmental satellites is at risk of degrading due to several factors. This includes the following: 1) loss of secondary polar-orbiting satellites due to reaching their nominal lifetimes, 2) decrease in the density of extratropical radio-occultation (RO) observations due to a likely delayed launch of the Constellation Observing System for Meteorology, Ionosphere and Climate-2 (COSMIC-2) high inclination orbit constellation, and 3) the risk of losing afternoon polar-orbiting satellite coverage due to potential launch delays in the Joint Polar Satellite System (JPSS) programs. In this study, the impacts from these scenarios on the National Oceanic and Atmospheric Administration (NOAA) Global Forecast System skill are quantified. Performances for several metrics are assessed, but to encapsulate the results the authors introduce an overall forecast score combining metrics for all parameters, atmospheric levels, and forecast lead times.