The Precipitation Radar is the first space-borne instrument designed to provide three-dimensional maps of storm structure. The measurements yield information on the intensity and distribution of the rain, on the rain type, on the storm depth and on the height at which the snow melts into rain. The estimates of the heat released into the atmosphere at different heights based on these measurements can be used to improve models of the global atmospheric circulation. The PR operates at 13.8 Ghz and measures the 3-d rainfall distribution over land and ocean surfaces. It defines a layer depth of perception and hence measure rainfall that actually reach the latent heat of atmosphere. It has a 4.3 Km resolution at radii with 220 Km swath.