Determination of Precipitation Profiles from Airborne Passive Microwave Radiometric Measurements

Christian Kummerow

Laboratory for Atmospheres, Goddard Space Flight Center, Greenbelt, Maryland

Ida M. Hakkarinen and Harold F. Pierce

General Sciences Corporation, Laurel, Maryland

James A. Weinman

Space Science and Engineering Center, University of Wisconsin, Madison, Wisconsin

ABSTRACT

This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two cases studies a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometeor density.