Japan's progress for the Global Precipitation Measurement (GPM)

The Global Precipitation Measurement (GPM) consists of a core satellite and a constellation of small satellites equipped with at least microwave radiometers. The primary purpose of GPM is three-hourly global precipitation observation. The core satellite has been grown up directly from the Tropical Rainfall Measuring Mission (TRMM) and to be equipped with a dual-wavelength radar (DPR) and a TMI-Iike radiometer. DPR is the primary and new sensor. Only the radar can directly observe three-dimensional precipitation structure. DPR would employ 13.6 GHz and 35 GHz radiowaves in order to have high accuracy rain estimate, higher sensitivity and liquid/solid particle discrimination capability. Algorithms for DPR is also under developing.