HUNTSVILLE, Ala. (June 20, 2016) — The mystery of why most of the most powerful lightning on Earth happens over the oceans isn’t solved, but a few of the usual suspects are no longer in custody.
It isn’t an instrument error, as some hypothesized. Nor is it the relative rarity of cloud-to-sea lightning allowing charges to build. And when it comes to cloud top heights, size apparently doesn’t matter.
It’s possible the increased presence of salt in the atmosphere plays a role, but if that is the case it probably has an accomplice. The evidence implicates ice crystal size, although air flowing back and forth along the land-sea boundary might also be involved.
“There isn’t one single mechanism that by itself justifies the stronger peak current we see in cloud-to-ground lightning over the oceans,” said Themis Chronis, a research scientist in the Earth System Science Center at The University of…
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