Automated Modifications to SNPP NUCAPS Soundings Using Surface Data for Severe Weather Analysis

The NOAA Unique Combined Atmospheric Processing System, or NUCAPS, combines satellite measurements of infrared and microwave radiation to provide global operational retrievals of vertical profiles of temperature and water vapor, along with atmospheric chemical composition. In particular, NUCAPS retrievals from the SNPP polar-orbiting satellite are generated using data from the CrIS and the ATMS instruments. With an afternoon orbit associated with a 1:30 pm LST equatorial crossing, the NUCAPS retrievals generated from the SNPP are well positioned in time to be used by forecasters assessing the pre-storm environment during the warm season. Evaluations of NUCAPS at the Hazardous Weather Testbed over the last few years have revealed that NUCAPS often has relatively large errors in its low-level temperature and moisture retrievals. These low-level values are critical for severe weather analysis via their use in calculating variables such as Convective Available Potential Energy (CAPE). A new project was therefore begun to combine NUCAPS retrievals with observed surface data from the Real Time Mesoscale Analysis (RTMA) and a simple mixed layer model to reduce the errors in the low levels and to make the retrieved soundings more reliable for analysis of severe weather potential. The ultimate goal is to characterize the performance of this correction and work on improvements toward its ultimate implementation into operations. This presentation will describe this data fusion product and show examples from its evaluation at the 2017 Hazardous Weather Testbed.