‘super rays’ aren’t a fantasy element. They exist not far from us, and the Mediterranean is one of the three places on the planet where they occur most often. They are rare, but dangerous. ‘Super lightning’ forms when the storm’s loading zone sits very close to the earth, making the charge region about 1000 times denser than usual.
This finding comes from a study on the so‑called ‘super bolts.’ These powerful strikes account for only about 1 percent of all recorded lightning, but they can damage critical infrastructure and ships.
“Super bolts” may be a tiny fraction of lightning, yet they remain a spectacular phenomenon, according to Avichay Efraim, a physicist at the Hebrew University of Jerusalem and the study’s lead author. He described the results in a statement.
A 2019 report highlighted that ‘superrays’ tend to cluster over the northeastern Atlantic Ocean, the Mediterranean Sea, and the Altiplano in Peru and Bolivia, one of the highest plateaus on Earth. Efraim explained that understanding why these zones attract stronger beams is essential.
The latest work offers the first global description of how ‘super lightning’ forms and distributes itself across land and sea. The research was published in the Journal of Geophysical Research: Atmospheres.
How does lightning occur?
Storm clouds generally rise to altitudes between 12 and 18 kilometers, spanning a wide temperature range. For lightning to develop, a cloud must reach the temperature threshold where air freezes, triggering electrification in the upper cloud and creating the lightning’s charge region.
Efraim questioned whether shifts in the freezing line height and the resulting changes in the loading zone could alter a storm’s capacity to generate super lightning. Earlier studies focused on whether factors like marine aerosols, emissions from shipping lanes, ocean salinity, or desert dust modulate these events, but those investigations covered only regional bodies of water and explained only part of the regional distribution of superrays. A global picture of the key drivers was still missing.
To uncover why super rays cluster in specific areas, Efraim and his team needed precise timing, locations, and energy measurements of individual lightning bolts. They gathered these data with an array of radio wave detectors.
Using the lightning data, researchers extracted core features of storm environments, including land and water surface elevations, the height of the loading zone, cloud base and top temperatures, and patterns of lightning concentration and aerosol presence. They then looked for correlations between these variables and the strength of the beams to understand what drives stronger super beams.
The closer to the surface, the denser the beam
The team found that, unlike earlier work, aerosols did not show a significant influence on the strength of super beams. Instead, a shorter distance between the charging zone and the surface—land or water—produces more energetic discharges.
Near‑surface storms allow higher energy lightning to occur because the reduced distance lowers electrical resistance, leading to a stronger current and more powerful beams.
The three regions with the most frequent super lightning—northeast Atlantic, the Mediterranean, and the Altiplano—share a common feature: loading zones are close to the surface, creating the conditions for intense discharges.
Understanding that surface proximity boosts super lightning helps scientists model how lightning forms and how climate change could alter future occurrences. Higher temperatures might increase weaker rays, but elevated moisture could counterbalance this effect, and researchers still do not have a definitive answer.
Looking ahead, the researchers plan to explore other contributing factors, such as changes in the magnetic field or solar activity, to further explain the formation of superrays.
Source: AGU Journal 2022, DOI 10.1029/2022JD038254
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