Comparison of Satellite, Model, and radiosonde Derived convective Available Potential Energy (CAPE) in the southern great plains region

Abstract

onvective Available Potential Energy (CAPE) is one of the physical quantities used by operational meteorologists when issuing severe weather convective watches and warnings. Recent advances in satellite technology could provide timely observations of atmospheric temperature and water vapor profiles over the continental United States. However, only limited validation exists in the literature to characterize uncertainties in CAPE derived from the new satellite sensors. In this study, ten years of Vaisala RS92 radiosonde observations from the Department of Energy Atmospheric Radiation Measurement Southern Great Plains (DOE ARM SGP) site were matched to overpasses of the NASA Aqua satellite from January 2005 through December 2014. Vertical profiles of temperature and water vapor from the NASA Atmospheric InfraRed Sounder (AIRS) were extracted in a region surrounding the DOE ARM SGP central facility near Lamont, Oklahoma. Surface-based CAPE was computed using software consistent with methods used by the National Weather Service Storm Prediction Center (SPC). The one-to-one correspondence of the AIRS-derived CAPE with the ARM radiosonde-derived CAPE has a correlation coefficient of only 0.34. Substitution of the ARM radiosonde surface values into the AIRS profiles improves the correlation to 0.95. The use of AIRS profiles above the surface level provides very similar surface-based CAPE values to those computed from Vaisala radiosondes. These results suggest that a merging of surface observations with satellite derived thermodynamic profiles could make better use of the satellite spatial coverage and temporal sampling for estimation of CAPE in near-real time.