Lightning does more than light the sky

As spring moves to summer, many places are finally seeing this year’s thunderstorm and tornado season come to an end. While there are few things as beautiful as a massive storm sprawling across an empty landscape, the storms don’t stick to the empty places, and can cause destruction and even death. A few years ago, I found myself writing a frantic Facebook post along the lines of, “Caught in tornado, hiding at gas station.” While I was ok, a 2 mile long swath of destruction passed through my neighborhood. As bad as it can be on the ground, we’re now learning these storms can trigger events through all layers of the atmosphere.

In a new study appearing in JGR Atmospheres, researchers led by Nikolai Ostgaard observed storms using optical and gamma ray detectors near Arecibo Observatory in Puerto Rico. This work was done in collaboration with the Atmosphere-Space Interactions Monitor on the International Space Station (ISS). They found that terrestrial gamma-ray flashes occur just as a positive intra-cloud lightning flash takes place. Along with this invisible, high-energy burst, detectors on the ISS above the storm were able to see a feature called Elves, which are emissions associated with electromagnetic pulses. Just 456 ms later, another Elve was produced with a negative cloud-to-ground lightning flash, 300 km away. This research is stunning and makes it clear that to really understand storms, we need to be observing them from above and below at the same time.