A combined microwave/infrared rain rate algorithm

A combined Microwave/Infrared Rain Rate Algorithm (MIRRA) is presented. His torically, infrared algorithms have benefited from excellent temporal sampl ing, but the relationship between cloud top temperature and surface rain ra te is very indirect. Alternatively, passive microwave algorithms are typica lly more physically direct and accurate, yet the associated sensors do not provide favourable temporal sampling for daily and monthly rainfall amounts . MIRRA is an attempt to utilize the strengths of these two broad approache s to rain rate measurement from space. The algorithm has been tested and de veloped using data from the TOGA-COARE campaign, with shipboard radar rain rate estimates used as truth. Results indicate enhanced performance in bias , correlation and rms error for MIRRA compared with other infrared and comb ined algorithms at the instantaneous scale, while retaining the good perfor mance of geostationary algorithms at daily and monthly scales.