Photo: NASA’s Marshall Space Flight Center / NASA
Lightning and thunderbolts have always been a source of curiosity and amazement.
Although dozens of bolts of lightning crackle at any moment in some place on Earth, 
these brief electrical discharges, which usually last less than 30 microseconds, are still unusually difficult to study.
However, satellites have greatly helped to deepen our understanding of lightning and the lightning that occurs on Earth in recent decades.
Sensors placed in space, such as the Lightning Imaging Sensor (LIS) on the International Space Station (ISS LIS ) have provided high-quality observations of lightning since the decade of 1990, allowing atmospheric scientists to quantify and map the global distribution of lightning.
The above map is based on multi-sensor lightning observations . Scientists at Los Alamos National Laboratory and the University of Alabama-Huntsville released an updated map in March 2021. Researchers at NASA’s Marshall Space Flight Center published a similar map of lightning activity, based on three years of ISS LIS observations, in July 2020.
The camera image sensor Lightning Sensor (LIS) is a space-based lightning sensor aboard the International Space Station (ISS). The ISS LIS instrument records the time of lightning occurrence, measures the radiant energy and estimates the location during the day and night with high detection efficiency.
Previous lightning activity maps assigned lightning a single coordinate on a map. By reprocessing all the OTD and LIS data, scientists were able to include the horizontal dimensions of the rays.
The incredible horizontal dimensions of some rays
“Our analysis explains the fact that lightning can propagate horizontally, not only vertically from the clouds to the ground”, explained Michael Peterson, of the Los Alamos National Laboratory. “One way to think of this new climatology is that it tells us how often an observer can expect lightning to be visible overhead, regardless of where the flash started or ended.”
“Some lightning bolts, we call them mega flashes, actually travel incredibly long horizontal distances, sometimes hundreds of kilometers,” added Peterson.
The longest lightning bolt evers recorded spanned 709 kilometres (440 miles) as it crackled through the skies of Argentina and Brazil during 11 seconds in 2018.
The lightning capitals of the world
With an average flash rate of 389 rays per day, Lake Maracaibo in northern Venezuela (shown at top) has the highest flare extension density in the world. The unique geography of that region fuels weather patterns that make it a magnet for thunderstorms and lightning.
The area along Lake Kivu, on the border of Rwanda and the Democratic Republic of the Congo, ranks second with an average of 368 flashes per day.
Some scientists anticipate that patterns will change as the world warms and weather fronts and storm tracks fit. By contributing to the production of nitrogen dioxide, a greenhouse gas, lightning also contributes directly to global warming.
“There is an urgent extra to look at the effect of climate change on lightning because the World Weather Agency recently added lightning to its list of essential climate variables,” said NASA Marshall atmospheric scientist Tim Lang.
With information from the NASA Earth Observatory
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