Sea surface temperature (SST) distribution in the tropical oceans observed by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). The microwave imaging technique's ability to penetrate clouds enables more frequent observation of SST than by infrared. In addition to the global capability of AMSR, the 6-GHz channels will measure SST more accurately. AMSR SST will be utilized for understanding various phenomena, including El-Ninõ, and will be applied to operational tasks such as fisheries forecasting.