Articles

The Global Precipitation Measurement (GPM) Core Observatory satellite operates in low Earth orbit, carrying two instruments for measuring Earth's precipitation and serving as a calibration standard for other members of the GPM satellite constellation. The satellite was developed and tested in-house at NASA Goddard Space Flight Center and launched from Tanegashima Space Center, Japan, on February 27th, 2014. The GPM Core Observatory orbits Earth at an inclination of 65 degrees, which enables it to cut across the orbits of other microwave radiometers and sample the latitudes where nearly all precipitation occurs. A non-sun-synchronous orbit that takes it around Earth roughly 16 times per day allows it to sample precipitation at different times of the day. Data is transmitted continuously to ground systems on Earth by the Tracking and Data Relay Satellite (TDRS) communications network.

NASA’s Integrated Multi-satellitE Retrievals for GPM (IMERG) algorithm combines information from the GPM satellite constellation to estimate precipitation over the majority of the Earth's surface. IMERG is particularly valuable over areas of Earth's surface that lack ground-based precipitation-measuring instruments, including oceans and remote areas. IMERG fuses precipitation estimates collected during the TRMM satellite’s operation (2000 - 2015) with recent precipitation estimates collected by the GPM mission (2014 - present) creating a continuous precipitation dataset spanning over two decades. This extended record enables scientists to compare past and present precipitation trends, enabling more accurate climate and weather models and a better understanding of Earth’s water cycle and rainfall and snowfall patterns. IMERG also enables a wide range of applications to help communities around the world make informed decisions for disasters, disease, resource management, energy production, food security, and more.