Estimated precipitation and latent heating profiles from combined Tropical Rainfall Measuring Mission TMI/PR/VIRS observations

The November 27, 1997 launch of the Tropical Rainfall Measuring Mission (TRMM) observatory provides the first opportunity to perform combined passive microwave/radar/infrared remote sensing of precipitation from satellite. A method for retrieving vertical precipitation/latent heating profiles using combined measurements from the TRMM Microwave Imager (TMI), Precipitation Radar (PR), and Visible and Infrared Scanner (VIRS) is presented. The TMI is a nine-channel passive microwave radiometer with dual polarization channels at 10.65, 19.35, 37, and 85.5 GHz and a vertical-polarization channel at 21.3 GHz. The PR is a 13.8 GHz single-parameter radar. The VIRS radiometer operates at visible/infrared wavelengths of 0.63, 1.61, 3.75, 10.8, and 12 microns. The TMI channels are to a large extent affected by the vertically-integrated cloud and precipitation water contents within clouds, while the PR senses the backscatter of radiation from precipitation within 0.25 km thick contiguous cloud layers. The VIRS, although not sensitive to precipitation directly, yields high-resolution measurements of cloud top temperature and overall cloud geometry. The combined TMI/PR/VIRS observations provide complementary information regarding the cloud morphology and spatial distribution of liquid/ice phase precipitation in tropical weather systems. From this information, the vertical and horizontal distributions of latent heating may be inferred.