A Long-Term Global Precipitation Dataset Based on the Latest Advances in GPM Algorithm Development and Sensor Intercalibration

The Global Precipitation Mission (GPM) Core Observatory, which was launched in February of 2014, provides several advances for satellite monitoring of precipitation from the previous TRMM mission including a dual-frequency radar, high frequency channels on the GPM Microwave Imager (GMI) for detection of frozen precipitation, and coverage over middle and high latitudes. Unlike TRMM, however, the GPM concept is about producing unified precipitation retrievals from a constellation of microwave radiometers to provide approximately 3-hourly global sampling. This involves intercalibration of the input brightness temperatures from the constellation radiometers, development of an apriori precipitation database using observations from the state-of-the-art GPM radiometer and radars, and accounting for sensor differences in the retrieval algorithm in a physically-consistent way. The latest V05 calibration and precipitation products were released for the GPM constellation (March 2014 – present) in May of 2017 and the extension of this data record back to the start of the TRMM mission (December 1997 – present) is scheduled for October of 2017. Work to extend this record back to July of 1987 for the available microwave radiometers over a 30-year period is ongoing. Algorithm development efforts have focused on incorporating the new GPM radar/radiometer observations, extending the retrievals to high latitudes, and improving the consistency of precipitation estimates over land including frozen precipitation and challenging surface conditions like frozen and/or snow-covered ground. This new long-term global precipitation dataset will expand the available precipitation products to the full constellation of available conical and cross-track scanning radiometers. It will provide a high-quality high-temporal resolution global precipitation dataset for use in a wide variety of hydrological, weather and climate research applications.