Hurricane rain slows the storm’s winds
DOI: 10.1063/PT.5.028770
Science : When a hurricane moves over water, its swirling winds draw moisture up into the atmosphere. As the moisture condenses, it releases heat, which adds energy to the hurricane. But the moisture also produces rain. As it falls, the rain acts as a source of friction and removes energy from the hurricane. To determine which effect predominates, Pinaki Chakraborty of Okinawa Institute of Science and Technology analyzed 15 years of North Atlantic hurricane data gathered by the Tropical Rainfall Measuring Mission. He and his colleagues then compared the data with predictions derived from a thermodynamic model. Model runs that included the rainfall friction not only reproduced the data more accurately than did runs that omitted it, but they also revealed that the rainfall reduced the speed of the hurricane’s winds by 10–30%.