Rainfall was scarce across much of the country in the month of September, pushing the eastern and southern thirds of the country into drought conditions. IMERG, the Integrated Multi-satellitE Retrievals for GPM, is a unified satellite precipitation product produced by NASA to estimate surface precipitation over most of the globe.

The intertropical convergence zone or “ITCZ” roughly forms a band that circumnavigates the Earth near the Equator where the northeast trade winds in the Northern Hemisphere converge with the southeast trade winds in the Southern Hemisphere. Sailors have often referred to it as the “doldrums” due to its generally light winds. Yet, the ITCZ is an important part of the global circulation as it forms the ascending branch of the Hadley circulation. This is ultimately driven by incoming solar radiation, which peaks near the Equator. This warms the air and the ocean, causing warm buoyant air to rise...

Latent heating (LH) arises predominantly from the release of heat associated with the condensation of water vapor into cloud droplets in clouds with active updrafts. Other sources of LH include ice deposition and freezing, while evaporation, melting and sublimation induce cooling, but condensation is the dominant heating term. Like a hot-air balloon, LH can keep air parcels warmer than their surrounding environment and therefore rising. On a large scale, LH is responsible for driving the ascending branch of the Hadley Circulation. LH is also an important component in the dynamics of a regional...

Spring is severe storms season here in the US, but not everyone has NEXRAD radar coverage; however, NASA’s TRMM and GPM satellites with their onboard radars have made it possible to search the entire global Tropics and midlatitudes and systematically identify areas where there are strong to intense thunderstorms. Researchers now headed by Dr. Chuntao Liu at Texas A&M University have built a comprehensive database of “precipitation features” based on regions of contiguous radar echoes from first the TRMM and now the GPM satellite. These precipitation features can then be mined to locate areas...

An El Niño that began to form last fall has matured and is now fully entrenched across the Pacific. Changes in sea surface temperatures, or SSTs, brought about by an El Niño affect the atmosphere, resulting in distinctive changes in the rainfall pattern across the Pacific Basin. These changes show up as anomalies or deviations in NASA’s analysis of climatological rainfall. This map shows sea surface temperature (SST) anomalies for the Pacific Basin, shown as degrees Celsius above or below average. Credit: NOAA Climate Prediction Center. In a typical El Niño, warmer than average SSTs off of the...

GPM celebrates its fifth anniversary since launching from Tanegashima Island, Japan on February 27, 2014. This milestone not only marks the launch but also the many scientific research accomplishments that GPM has made in advancing our understanding of precipitation, from light rain to intense thunderstorms, to further our understanding of the water cycle. Here are five of GPM’s most significant research accomplishments and their contributions to weather and climate science in its first five years in space: Snowfall and Cold Season Precipitation An image of GPM’s DPR concept of dual-frequency...

In this video GPM Project Scientist Dr. Gail Skofronick-Jackson explains how scientists can measure the size, shape and distribution of snow particles, layer by layer, in a storm using GPM. The Global Precipitation Measurement mission is an international satellite project that provides next-generation observations of rain and snow worldwide every three hours.