WATER-VAPOR PROFILE RETRIEVALS FROM SSM T-2 DATA CONSTRAINED BY INFRARED-BASED CLOUD PARAMETERS/

An algorithm has been developed for the retrieval of water vapour prof iles from passive microwave observations near 183 GHz. The algorithm t reats clouds explicitly and can incorporate cloud information from oth er sources. As a test, the algorithm has been configured to use data f rom the SSM/T-2 on the DMSP polar orbiting satellite series. Cloud top temperature and phase information have been derived from the AVHRR on the NOAA polar orbiting satellite series. Obtaining suitable coincide nces between the SSM/T-2 and the AVHRR is challenging but two reasonab le cases have been found. In one case, a liquid cloud injected into th e retrieval results in significant improvement in the accuracy and ver tical resolution in the neighbourhood of the cloud top. A cloud base i s a by-product of the algorithm, but its validity has yet to be establ ished. In the other case, a cirrus cloud injected into the algorithm r esulted in little change in the retrieval which indicates that the alg orithm was performing well in the cloud top vicinity (400 mb).