Seminars

Lecturer: Gang Hong (Texas A&M)
Date: 2009-02-05 10:30
Place: Aniara

Detection of Tropical Deep Convective Clouds from Satellite Microwave Measurements and Its Application to Cloud Climatology

Gang Hong

Department of Atmospheric Sciences
Texas A&M University



Deep convective clouds play a major role in the Earth's climate by transporting heat, moisture, and momentum from the lower to the upper troposphere. Those penetrating into the tropical tropopause layer (TTL) also contribute to the exchange of air between the troposphere and the stratosphere. An algorithm to detect tropical deep convective clouds using the three water vapor channels around 183.3 GHz from the AMSU-B has been developed. This algorithm has been used to survey interannual to diurnal variations of tropical deep convective clouds and convective overshooting using the AMSU-B aboard the NOAA polar orbiting satellites from 1999 to 2005. The most frequently used technique for objectively extracting cloud information from satellite images is the infrared threshold technique. Using measurements from the infrared sensor and precipitation radar aboard TRMM satellite, the effect of cirrus clouds on the diurnal cycle of tropical deep convective clouds has been investigated. Time lags of the diurnal cycle of deep convective clouds from the infrared measurements with respect to that from the precipitation radar are found.
It has been found that the radiation forcing of tropical deep convective clouds is sensitive to their optical and microphysical properties. The single-scattering properties of frozen hydrometeors particles are fundamental to the radiative transfer in convective clouds, and are thereby the basis for estimating the optical and microphysical properties of these clouds. The scattering and absorption properties of several typical nonspherical ice particles in ice clouds using the discrete dipole approximation method at microwave frequencies have been developed for objectives of microwave remote sensing of convective clouds and ice clouds.


Created 2009-01-30 11:31:12 by Mats Holmström
Last changed 2009-01-30 11:31:12 by Mats Holmström