Status of AMSR-E land and coastal rainfall algorithms

After several years of efforts to improve the TRMM Microwave Imager (TMI) rain algorithm, the algorithm developers designed the initial AMSR-E algorithm to produce similar rainfall rates as from the TMI. However, not all the TMI and AMSR-E channels are calibrated to each other, they have slightly different frequencies and resolutions, there are slight differences in the algorithm details, and the AMSR-E estimates cover all but the polar regions, compared to the tropical-only estimates from TMI. Due to a combination of these factors, the initial AMSR-E rainfall algorithm does not perform as well as the similar TMI rainfall algorithm.

As a result, some AMSR-E algorithms (such as for rainfall rate) are undergoing frequent (3-month) modifications during the first year of products released to the public; the initial release was March 1, 2004. The status and quality of these different product releases are presented so that users will better understand their value and limitations.