Since rain and freshwater flooding are the number one causes of death from hurricanes in the United States over the last 30 years, better understanding of these storms is vital for insuring public safety. A recent study funded by NASA and the National Science Foundation offers insight into patterns of rainfall from tropical storms and hurricanes around the world. Researchers at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, Miami, and the National Oceanic and Atmospheric Administration Atlantic Oceanographic and Meteorological Laboratory’s Hurricane Research Division, Miami, used data from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite to show how rain falls at different rates in different areas of a storm.
The results were published in the July issue of the journal Monthly Weather Review. The results are already being used in a model developed at the Hurricane Research Division to estimate rainfall accumulation related to tropical cyclones. The findings are important because they may help in the development of better forecasts. The TRMM satellite offers the best measurements of how and where rain falls around tropical cyclones. This is because its orbit is low to the Earth, allowing more detailed information on storms, and it was designed to cover the tropics. Tropical cyclones consist of winds rotating around low-pressure centers in the tropics that can develop into everything from tropical storms to Category 5 hurricanes.
Normally, the only way to accurately measure rain falling from a hurricane is when it gets close enough to the coast to be picked up by National Weather Service radars, or by rain gages. Since TRMM is space-based, researchers can assess the rainfall over vast tracts of ocean, where these storms spend most of their lives.