Advancing Extreme Weather Monitoring from Space: From TRMM to GPM

The Tropical Rainfall Measuring Mission (TRMM), launched in 1997, uses active and passive microwave instruments to confirm the validity of tropical rainfall estimates derived from operational passive microwave sensors and provides a foundation for merging rainfall information from other satellites. High-resolution microwave information is important for fixing the locations of tropical cyclone tracks as well as establishing accurate initial positions to effectively forecast tropical cyclone progression. The TRMM Microwave Imager (TMI) is designed to “see” through clouds and provide high-resolution rainfall structure information within tropical cyclones. TRMM’s Precipitation Radar (PR) is designed to provide vertical structure information within tropical cyclones. Together, TRMM PR and TMI data have been used to establish key characteristics of the distribution and variability of rainfall in tropical cyclones and obtain insights into storm structure, intensity, and environmental conditions.

Extreme precipitation over hours to months can trigger disastrous flooding and/or landslides depending on the area’s topography, land use, and climate. Several merged, multi-satellite products have been developed to provide near real-time precipitation information valuable for modeling and monitoring these hydrometeorological events. These include TRMM’s Multi-Satellite Precipitation Analysis (TMPA) product.

Current satellites provide better than 3-hour mean revisit times over 45% of the globe. GPM’s satellite constellation will enable the collection of coincident measurements over a wider range of latitudes, bringing coverage up to 90% during the peak year of the mission. The advanced radar-radiometer measurement system onboard the GPM Core Satellite, scheduled for launch in 2013, will offer greater measurement sensitivity to light rain and falling snow. Through enhanced spatial and temporal precipitation measurements, the GPM mission will provide rapidly disseminated precipitation products to advance predictive capabilities for natural hazards and extreme weather events from the tropics to high latitudes. Additional information about both TRMM and GPM can be accessed at pmm.nasa.gov.