Scientists are using water temperature to help predict when hurricanes are about to make a dangerous change in intensity.
Hurricanes suddenly gain strength in part because they pass over rings, swirls and eddies of unusually deep, warm water — “bumps” that can be 2 inches higher than the rest of the ocean.
Scientist Gustavo Goni and others have developed a tool — the tropical cyclone heat potential — to measure how warm the water is in these areas, and how deep the higher temperatures reach. They measure the “bumps” with precise satellite altimeters.
The ocean’s surface must be at least 78.8 degrees Fahrenheit for hurricanes to form and thrive.
Researchers have found those temperatures can range from 78.8 degrees at 45 feet to 87.8 degrees at 600 feet — enough to make a big difference in a hurricane’s strength, said Goni, who works at the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory near Key Biscayne.
“We have examples we can show of hurricanes that intensified after passing over these very warm areas,” he said.
Cases like Hurricane Mitch, which killed 9,000 in central America in 1998 when it suddenly intensified from Category 3 to Category 5, make such discoveries important, meteorologists say.
Meteorologist Michelle Mainelli of the National Hurricane Center said the measurement is currently being used in computer forecast models.