The skies prefer to hurl down lightning bolts over Florida, the Himalayas and central Africa. Oceans and the poles, however, mostly escape the electric wrath of nature. So conclude scientists perusing a new composite map of satellite images that record where and when lightning strikes across the planet.
NASA researchers made the observations using two weather satellites, the first one launched in 1995, equipped with special near-infrared detectors that can spot lightning flashes even in daytime.
“For the first time, we’ve been able to map the global distribution of lightning,” said Hugh Christian, a lightning scientist at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
“These optical sensors use high-speed cameras to look for changes in the tops of clouds, changes your eyes can’t see.”
Florida experiences a particularly high number of strikes because of an unusual weather pattern, according to Dennis Boccippio, an atmospheric scientist with the National Aeronautics and Space Administration. Westward breezes from the Atlantic Ocean and eastward gusts from the Gulf of Mexico collide over the flat peninsula, pushing ground air up and spawning frequent thunderstorms, he said.
Lightning strikes kill about 10 people every year in Florida, twice the rate in any other state.
The Himalayas are another electrical hot spot, as the extremely high mountains force Indian Ocean air masses to bump into one another.
Yet the world lightning king is central Africa. “There you get thunderstorms all year round. It’s a result of weather patterns, air flow from the Atlantic and enhancement by mountainous areas, “Christian said.
Meanwhile, in the Arctic, Antarctic and the oceans, low-lying air rarely heats up enough to generate thunderstorms and lightning. “People living on some of the islands of the Pacific don’t describe much lightning in their language,” Christian said.
The satellite data suggest some seasonal patterns in the sky bolts. In the Northern Hemisphere, strikes tend to take place in the summer. But around the equator, most appear in the spring and autumn.