Radiances from current polar orbiting IR and MW sounders are used to infer temperature and moisture profiles in the troposphere in a physical retrieval algorithm. Specifications 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 provides an opportunity to derive very accurate upper atmospheric temperature profiles (from 350 hPa up to 3 hPa) 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 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. Simulation tests indicate that RO improves IR and MW retrievals of temperature and moisture in the upper tropopause. It remains to prove this with real data.