How did a lake in Venezuela become the world’s lightning capital?
By tracking lightning around globe over 16 years, scientists have found that Lake Maracaibo in northwest Venezuela is the lightning capital of the world.
This means that every square kilometer there faces 233 flashes of electricity per year, says a group of scientists from the United States and Brazil. It’s the topography and climate around Lake Maracaibo – hot and humid, mixed with cool breezes from the nearby Andes Mountains – that makes it the ideal destination for thunderstorms.
And at South America’s largest body of water, they happen almost every night: 297 days per year on average, according to lightning researchers who published their findings in the Bulletin of the American Meteorological Society.
“These thunderstorms are very localized and their persistent development anchored in one location accounts for the high flash rate density,” write the researchers in their paper.
To determine the world’s hotspot for lightning, scientists looked at data collected by the Lightning Imaging Sensor onboard a NASA Tropical Rainfall Measurement Mission satellite. The sensor looks at near-infrared light to catch flashes that happen during daylight.
"It's taking very rapid updates," Daniel Cecil, a NASA lightning scientist, told LiveScience last year. "So it will measure a background scene, and then with very rapid updates check to see if there's a sudden change in brightness from that background scene," he said. If there is, the sensor records that as a flash of lightning.
Lake Maracaibo has long been known for its prodigious lightning. But before this analysis, Africa’s Congo Basin was thought to be the epicenter of thunderstorms, based on a few years of data collected by satellite between 1995 and 2000. The current findings are based on data collected over a much longer period of time, between 1998 and 2013.
"We can now observe lightning flash rate density in very fine detail on a global scale," Richard Blakeslee, a scientist at NASA's Marshall Space Flight Center, which runs the lightning sensor, said in a NASA announcement.
Africa is still a lightning mecca, according to the study, with the most lightning hotspots. The continent is home to six of the world's top 10 sites for lightning activity, which tends to concentrate near the equator, usually striking land instead of sea.
The majority of the hotspots are by Lake Victoria in central Africa, the largest tropical lake in the world, and other lakes along the East African Rift Valley, which have a similar geography to Lake Maracaibo.
Lightning behavior – such as frequency or intensity – can change during storms including tornadoes and hurricanes. If scientists can understand what the behavioral patterns mean, it could help them better predict other storms, increasing the lead time for warnings, say study authors.
The researchers are planning to send a new lightning imaging sensor in October to geostationary orbit (over the Earth's equator), where it will track storms as they move across the planet.
