Constantly scanning the Earth’s surface, the TRMM Microwave Imager (TMI) allows scientists to both track tropical cyclones and forecast their progression. Used by NOAA’s National Hurricane Center (NHC), the Joint Typhoon Warning Center (JTWC), and tropical cyclone centers in Japan, India, Australia and other countries, detailed microwave information provides data on the location, pattern and intensity of rainfall.
Complimenting the TMI is the TRMM’s Precipitation Radar (PR), which turns two dimensional images into 3D by providing data on vertical rainfall structure. Scientists use PR data to verify their tropical cyclone computer models. They also use the data to understand the distribution and movement of latent heat throughout the storm, particularly in the development of hot towers in the wall of clouds around the eye, which have been linked to rapid intensification. Together, TRMM TMI and PR data help scientists establish key characteristics of where, how and why rain falls in tropical cyclones as well as to better understand storm structure, intensity and the environmental conditions that cause them.
Currently the TRMM Mission observes cyclones at mid to low latitudes around the equator, flying in an orbit that moves between 35°S and 35°N — the distance from the southern tip of Africa to the Mediterranean Sea. The GPM Mission extends tropical cyclone tracking and forecasting capabilities into the middle and high latitudes, covering the area from 65° S to 65°N — from about the Antarctic Circle to the Arctic Circle. This orbit will provide new insight into how and why some tropical cyclones intensify and others weaken as they move from tropical to mid-latitude systems. The sensors onboard other satellites within the GPM constellation along with GPM Core Observatory sensors provide the detailed and global observations needed to estimate, monitor and forecast extreme rainfall that may trigger natural hazards, such as flooding or landslides.