Deciphering the Science Behind Superbolts: Unraveling Earth’s Most Powerful Lightning Strikes

New research findings have illuminated the origins of superbolts, those astonishingly potent lightning strikes that occur when storm clouds’ electrical charging zones draw near to land or water surfaces. This revelation sheds light on the geographical disparities in superbolt occurrences and holds the potential to provide insights into the impacts of climate change on these remarkable meteorological phenomena.

When the electrical charging zone of a storm hovers close to the Earth’s surface, it gives rise to superbolts, lightning bolts that can be a staggering 1,000 times more potent than the typical lightning strike.

A recent study reveals that superbolts are more likely to strike when a storm cloud’s electrical charging zone is in close proximity to the land or ocean’s surface. This phenomenon has led to the emergence of superbolt “hotspots” over certain oceans and towering mountain ranges.

Superbolts constitute less than 1% of the total lightning activity, but their sheer power is awe-inspiring. While an average lightning strike delivers approximately 300 million volts, superbolts surge to an astonishing 1,000 times that intensity, capable of inflicting significant damage to infrastructure and vessels, according to the study’s authors.

Avichay Efraim, a physicist at the Hebrew University of Jerusalem and the lead author of this research, remarked, “Superbolts, despite their rarity in the realm of lightning, stand as a magnificent natural phenomenon.”

Building upon Earlier Studies and Fresh Insights

A 2019 report identified clusters of superbolts over regions such as the Northeast Atlantic Ocean, the Mediterranean Sea, and the Altiplano in Peru and Bolivia, one of Earth’s highest plateaus. Avichay Efraim and his team embarked on a quest to decipher the factors contributing to the preferential formation of superbolts in specific locations.

This novel study provides the first comprehensive explanation for the genesis and distribution of superbolts across land and sea worldwide. The research findings were published in the Journal of Geophysical Research: Atmospheres, a publication dedicated to advancing the understanding of Earth’s atmosphere and its intricate interactions with other components of the Earth system.

Storm clouds typically extend to altitudes ranging from 12 to 18 kilometers (7.5 to 11 miles), encompassing a broad spectrum of temperatures. However, for lightning to manifest, a cloud must straddle the boundary where air temperatures reach 0 degrees Celsius (32 degrees Fahrenheit). Above this freezing line, within the upper echelons of the cloud, the electrification process unfolds, leading to the creation of the lightning’s “charging zone.” Efraim pondered whether variations in the altitude of the freezing line, and consequently the height of the charging zone, could influence a storm’s propensity to generate superbolts.

Analyzing Critical Factors

Previous studies explored potential influences on superbolt strength, including sea spray, emissions from shipping lanes, ocean salinity, and even desert dust. However, these studies were confined to regional bodies of water and could account for only a portion of the regional distribution of superbolts. A comprehensive global explanation for superbolt hotspots remained elusive.

To unravel the mysteries of superbolt clustering, Efraim and his collaborators required precise data on the timing, location, and energy of specific lightning strikes. This data was obtained from an array of radio wave detectors. They leveraged this lightning data to extract crucial characteristics of the storms’ environments, encompassing factors such as the height of land and water surfaces, charging zone elevation, temperatures at the cloud’s upper and lower limits, and aerosol concentrations. Subsequently, they sought correlations between each of these factors and the strength of superbolts, yielding valuable insights into what influences the intensity of lightning—and what does not.

In a departure from earlier studies, the researchers discovered that aerosols did not exert a significant impact on the strength of superbolts. Instead, a closer proximity between the charging zone and the land or water surface correlated with the occurrence of more energized lightning. Storms in close proximity to the Earth’s surface facilitate the formation of higher-energy bolts because shorter distances entail reduced electrical resistance and consequently higher electrical currents. These higher currents translate into more robust lightning bolts.

The three regions that experience the highest incidence of superbolts—the Northeast Atlantic Ocean, the Mediterranean Sea, and the Altiplano—share a common characteristic: minimal distances between the charging zones of lightning and the Earth’s surface.

Efraim emphasized, “The correlation we observed was remarkably clear and significant, particularly across these three regions. This marks a substantial breakthrough for our research.”

Implications and Future Investigations

Understanding that a reduced distance between a surface and a cloud’s charging zone leads to a higher frequency of superbolts will empower scientists to assess how climate variations might impact the occurrence of superbolt lightning in the future. While warmer temperatures may result in an increase in less intense lightning, increased atmospheric moisture could offset this effect. Currently, there is no definitive answer to this complex interplay of factors.

Moving forward, Efraim and his team are committed to exploring additional factors that could contribute to the formation of superbolts, including the influence of the magnetic field and changes in the solar cycle.

Efraim concluded, “There remains much to uncover, but what we’ve achieved here constitutes a significant piece of the puzzle. Our journey of discovery is far from over, and there is much more to explore.”

Reference: “A Possible Cause for Preference of Super Bolt Lightning Over the Mediterranean Sea and the Altiplano” by Avichay Efraim, Daniel Rosenfeld, Robert Holzworth, and Joel A. Thornton, 19 September 2023, Journal of Geophysical Research Atmospheres.
DOI: 10.1029/2022JD038254

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More about Superbolt Lightning

• Journal of Geophysical Research: Atmospheres: The publication where the research findings on superbolts were published.
• Superbolt Lightning: Additional information about superbolts and their characteristics.
• Climate Change and Lightning: Information on the relationship between climate change and lightning activity.
• Atmospheric Science: Resources and articles related to atmospheric science, including studies on lightning phenomena.