A simulation study combining radio occupation data and IR/MW radiances to derive temperature and moisture profiles

摘要

Radiances from current polar orbiting infrared (IR) and microwave (MW) sounders are used to infer temperature and moisture profiles in the troposphere in a physical retrieval algorithm. Specification of the tropopause and the surface are necessary boundary conditions in the profile retrieval. Good definition of the tropopause has been elusive via radiometric approaches. The Global Positioning System (GPS) provides an opportunity to derive very accurate upper atmospheric temperature profiles by using radio occultation (RO) techniques. In this paper we show that the combination of radiometric (IR and MW) and geometric (RO) information yields improved tropospheric temperature and moisture profiles when compared to those inferred from either system alone. RO and IR/MW measurements are simulated from the National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service (NOAA/NESDIS) NOAA88 global radiosonde data set. Retrievals are performed using a statistical regression approach. Surface data are set as the lowest level of a radiosonde profile. A variety of simulation tests will be presented to illustrate the impact of surface and tropopause information on the temperature and humidity retrievals.