CAPE CANAVERAL, Fla. — NASA Administrator Charles Bolden and Japan Aerospace Exploration Agency (JAXA) President Keiji Tachikawa signed an agreement defining the terms of cooperation between the agencies on the Global Precipitation Measurement (GPM) mission. The ceremony took place Thursday at the Kennedy Space Center Visitor Complex.

Building on the success of the NASA-JAXA Tropical Rainfall Measuring Mission (TRMM), GPM will begin the measurement of global precipitation, a key climate factor. It is an international collaboration that includes NASA and JAXA, with anticipated contributions of data from other international partners.

GPM is also the cornerstone of the multinational Committee on Earth Observation Satellites Precipitation Constellation that addresses one of the key observations of the Global Earth Observation System of Systems. The heart of the GPM mission is a space-borne core observatory which serves as a reference standard to unify measurements from a constellation of multinational research and operational satellites carrying microwave sensors.

GPM will provide uniformly calibrated precipitation measurements globally every 2 to 4 hours for scientific research and societal applications. For the first time, the GPM core observatory sensor measurements will make detailed observations of precipitation particle size distribution, which is key to improving the accuracy of precipitation estimates by microwave radiometers and radars.

The GPM core observatory will carry a Dual-frequency Precipitation Radar (DPR), which operates at Ku and Ka band frequencies, and a multi-channel GPM Microwave Imager (GMI) operating from 10-183 GHz. The DPR will have greater measurement sensitivity to light rain and snowfall compared to the TRMM radar. The GMI uses a set of frequencies that have been optimized to retrieve heavy, moderate, and light precipitation estimates.

Through the agreement, NASA is responsible for the GPM core observatory spacecraft bus, the GMI carried by it, and a second GMI to be flown on a partner-provided Low-Inclination Observatory. JAXA will supply the DPR for the core observatory, an H-IIA rocket for the core observatory’s launch in July 2013 and data from a conical-scanning microwave imager on the upcoming Global Change Observation Mission satellite.

For more information about GPM, visit: http://nasascience.gov/missions/gpm

For more information about TRMM, visit: http://nasascience.nasa.gov/missions/trmm