Deriving Atmospheric Temperature of the Tropopause Region–Upper Troposphere by Combining Information from GPS Radio Occultation Refractivity and High-Spectral-Resolution Infrared Radiance Measurements

• Published in: Journal of applied meteorology (1988) 2008-09, Vol.47 (9), p.2300-2310
• Main Authors: Borbas, Eva E., Menzel, W. Paul, Weisz, Elisabeth, Devenyi, Dezso
• Format: Article
• Language: English
• Subjects: Air; Atmospheric infrared sounder; Atmospheric temperature; Atmospherics; Bayesian analysis; Data assimilation; Datasets; Earth, ocean, space; Estimation methods; Exact sciences and technology; External geophysics; General properties of the high atmosphere; Geographic information systems; Global Positioning System; Global positioning systems; GPS; Light refraction; Meteorology; Navigation systems; Physics of the high neutral atmosphere; Radio occultation; Refractivity; Retrieval; Sample size; Satellite navigation systems; Satellite systems; Statistics; Temperature; Temperature profiles; Tropopause; Troposphere
• ISSN: 1558-8424; 0894-8763; 1558-8432; 1520-0450
• DOI: 10.1175/2008JAMC1687.1

Global positioning system radio occultation (GPS/RO) measurements from the Challenging Minisatellite Payload (CHAMP) and Satelite de Aplicaciones Cientificas-C (SAC-C) satellites are used to improve tropospheric profile retrievals derived from theAquaplatform high-spectral-resolution Atmospheric Infrared Sounder (AIRS) and broadband Advanced Microwave Sounding Unit (AMSU) measurements under clear-sky conditions. This paper compares temperature retrievals from combined AIRS, AMSU, and CHAMP/SAC-C measurements using different techniques: 1) a principal component statistical regression using coefficients established between real (and in a few cases calculated) measurements and radiosonde atmospheric profiles; and 2) a Bayesian estimation method applied to AIRS plus AMSU temperature retrievals and GPS/RO temperature profiles. The Bayesian estimation method was also applied to GPS/RO data and the AIRS Science Team operational level-2 (version 4.0) temperature products for comparison. In this study, including GPS/RO data in the tropopause region produces the largest improvement in AIRS–AMSU temperature retrievals—about 0.5 K between 100 and 300 hPa. GPS/RO data are found to provide valuable upper-tropospheric information that improves the profile retrievals from AIRS and AMSU.