Remote Sounding of Cloud Parameters from a Combination of Infrared and Microwave Channels

Abstract

This study explores the utilization of both infrared and microwave sounding channels for the inference of the high and low cloud parameters. The necessary parameterized equations for infrared and microwave radiative transfer have been derived for applications to remote sensing from satellites. Retrieval programs have been developed for the determination of the high cloud top height, high cloud thickness, low cloud top height, surface emissivities, and cloud liquid water content successively from a set of HIRS and SCAMS channels. Analyses involving random errors in the assumed temperature and water vapor profiles and measurement errors in the theoretically computed radiances and brightness temperatures have been carried out to investigate the sensitivity of these errors on the retrieval program. Results of error analyses reveal that the cloud retrieval technique developed in this paper appears to be theoretically rigorous and practically feasible. The retrieval technique is then applied to Nimbus 6 HIRS and SCAMS data for a number of carefully selected cases associated with summertime convective cloud systems. Results of the satellite retrieved cloud parameters based on a combination of infrared and microwave channels appear to be in qualitative agreement with the available synoptic, surface and radar observations.