Observational Surface-Based CAPE from Merged Hyperspectral IR Satellite Sounder and Surface Meteorological Station Data
Abstract
Satellite-derived temperature and moisture soundings provide information about the diurnal atmospheric vertical thermodynamic structure in and above the boundary layer occurring between successive routine National Weather Service (NWS) radiosonde launches. In particular, polar-orbiting satellite soundings become critical to the computation of stability indices over the central United States in the mid-afternoon, when there are no routine NWS radiosonde launches. Accurate measurements of surface temperature and dewpoint temperature are key in the calculation of severe weather indices, including surface-based convective available potential energy (SBCAPE). CAPE is a well-established measure of buoyancy-driven atmospheric instability that is computed from vertical profiles of temperature and water vapor and is important in forecasting severe weather. This work addresses a shortcoming of current operational infrared-based satellite soundings, which underestimate the surface parcel temperature and dewpoint when CAPE is non-zero. This leads to a systematic underestimate of SBCAPE. This paper demonstrates a merging of satellite-derived vertical profiles with surface observations to address this deficiency. The National Oceanic and Atmospheric Administration (NOAA) Center for Environmental Prediction (NCEP) Meteorological Assimilation Data Ingest System (MADIS) hourly surface observation data are blended with satellite soundings derived using the NOAA-Unique Combined Atmospheric Processing System (NUCAPS) to create a greatly improved SBCAPE calculation. NUCAPS uses brightness temperature observations from the Cross-track InfraRed Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) onboard the NASA Suomi-NPP (SNPP) satellite. SNPP has overpass times at 0130 and 1330 local times. A six-month time period, April through September 2018, was analyzed over CONUS to provide a comprehensive analysis of the impact of using surface observations in satellite SBCAPE calculations. This paper will discuss the value of continuous hourly observations for the monitoring of atmospheric stability and future options for sounding from geostationary orbit.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A11T2830B
- Keywords:
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- 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES