Lightning bolts struck as storms got stronger
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A study of lightning inside the eye of hurricanes by University of Hawaii researchers could lead to better forecasts of approaching storms.
Using data from sensors, researchers noted in 2005 an increase in lightning inside Hurricanes Katrina and Rita as their wind speed picked up. Their findings suggest a possible relationship between lightning activity and the strength of a hurricane.
If further tests confirm that link, forecasters could gain a valuable tool to measure the power of future hurricanes long before landfall. The land-based sensors can detect lightning in storms thousands of miles at sea.
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Steven Businger, a meteorology professor at the University of Hawaii, with a long-range lightning sensor at Lihue airport on Kauai. Researchers hope the sensors will help forecasters better measure the strength of hurricanes long before landfall.
A growing network of land-based sensors that can detect lightning inside storms developing thousands of miles at sea could become a valuable tool to forecast the strength of hurricanes long before they reach shore, according to a study by University of Hawaii researchers.
Researchers observed a spike in lightning strikes in the eye of hurricanes Katrina and Rita in 2005 as they packed wind speeds above 155 mph.
"We actually saw that each storm contained a lightning outbreak, a whole lot of lightning within the eye wall, as they were rapidly intensifying," said lead author Kirt Squires, who graduated from UH's meteorology program in December.
Previous technology was only able to measure about 20 percent of lightning inside storms spinning 500 miles offshore. Sensors can now read 80 percent of activity in hurricanes located as far as 4,000 miles from land, Squires said.
Squires and study co-author Steven Businger, a meteorology professor at UH, analyzed data from the two Category 5 storms in the Atlantic with long-range lightning sensors. Their study, which will appear in the upcoming issue of the American Meteorological Society's Monthly Weather Review, also looked at information from a NASA satellite and instruments aboard airplanes flying into the hurricanes.
Businger cautioned that more tests are needed before scientists can hail a link between a hurricane's power and the amount of lightning it creates. While there is a relationship among lightning, rainfall and heat inside storms, he noted some strong systems have failed to show lightning for long periods.
"You would expect that there is some relationship between lightning and the evolution of the storm, but it's very complex," he said. "But the promise that these data hold is that they will provide for better forecasts."
Satellite imagery and other weather data have allowed forecasters to make fairly accurate projections about a hurricane's path but not its strength, Squires said. That could change if researchers are able to prove a correlation between lightning and a storm's energy, he said.
"When you start to get a pattern, you can use the lightning data to help better forecast the intensity," he said.
There are four such sensors in the Pacific, including one at Lihue Airport and another in Kona. They were used to monitor Hurricane Flossie, which reached Category 4 but weakened as it passed about 90 miles south of the Big Island last month with little lightning activity.
Businger said he is awaiting funding for proposals to install eight additional sensors, which are about 6 feet tall and cost about $150,000 each, in places like Guam, Midway Atoll and even Okinawa, southern Japan, possibly by next summer.
They would add to the nearly 200 sensors that make up the North American Lightning Detection Network, which covers the Gulf of Mexico and the Atlantic and Pacific oceans.