Evaluation of Atmospheric Stability Indices Derived from NUCAPS S-NPP Soundings under Different Cloudy Conditions

Atmospheric static stability plays a crucial role in determining where and when convective systems have the potential to develop. Because of that, the meteorological community has developed atmospheric stability indices, which are computed from radiosonde observations (RAOBs). However, the traditional analysis of the atmospheric stability suffers constraints due to the spatial and temporal coverage limitations of RAOBs. Within this context, satellite-derived thermodynamic profiles can assist operational forecasters in the task of analyzing the synoptic-scale structure of atmospheric stability.

Atmospheric vertical profiles of temperature and moisture are among the suite of Environmental Data Records (EDRs) products retrieved by the National Oceanic and Atmospheric Administration (NOAA) Unique Combined Atmospheric Processing System (NUCAPS) from the processing of the Cross‐track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) radiances. Both state‐of‐the‐art instruments are currently onboard the Suomi National Polar‐orbiting Partnership (S‐NPP) spacecraft, first satellite of the Joint Polar Satellite System (JPSS) U.S. operational series. One of the important components of the NUCAPS is its cloud clearing module developed to produce cloud-cleared infrared radiances, which allows the derivation of vertical profiles under non-precipitating conditions (clear, partly cloudy, and cloudy).

This work will present results for the first investigation of the performance of the NUCAPS S‐NPP stability products validated according to different cloudy conditions motivated by the assumption that such performance varies depending on the existing cloud cover. For this purpose, statistical comparisons against ground-based radiosondes collocated within a maximum radius of 50 km and ±1-h time difference will be performed for the midlatitudes (60^o to 30^o) and tropics (30^o to 30^o). In this process, the NUCAPS S‐NPP Cloud Fraction EDR product will be used to determine the cloud cover over the area corresponding to each collocated NUCAPS/RAOBs pair. In addition, statistical comparisons between the NUCAPS S‐NPP Cloud Fraction and the Visible Infrared Imaging Radiometer Suite (VIIRS) Cloud Cover/Layers EDR are planned to validate the NUCAPS product. VIIRS is another key instrument aboard the SNPP satellite, which is also planned (as well as CrIS and ATMS) to be present on the future satellites of the JPSS series. This research effort is important for a complete understanding of the applicability and usefulness of NUCAPS stability products to the operational forecasting.