Making a Superbolt: Reconciling Observations of the Optically Brightest Lightning on Earth From Different Satellites

Journal Article · 18 August 2023 · Earth and Space Science

DOI: https://doi.org/10.1029/2023ea003001 · OSTI ID:2432311

Peterson, Michael Jay  ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

We previously documented geographic distributions of the optically brightest lightning on Earth—known as “superbolts”—using two space-based instruments: the photodiode detector (PDD) on the Fast On-orbit Recording of Transient Events (FORTE) satellite and the Geostationary Lightning Mapper (GLM) on NOAA's Geostationary Operational Environmental Satellites. In this study, we further examine the superbolts identified by the PDD and GLM to reconcile the differences between their geographic distributions. We find that both the physical extent of the parent flash and the development speed of its leaders are important for making a superbolt. The oceanic PDD superbolts tend to occur early in flashes that rapidly expand laterally into long horizontal “megaflashes.” The top GLM superbolts occur over land at later times in particularly large megaflashes. These land-based flashes grow more slowly until they extend over multiple hundreds of kilometers. The FORTE PDD missed these delayed superbolts due to limitations in its triggering. Coincident Tropical Rainfall Measuring Mission measurements show that the warm season megaflash superbolts detected by Lightning Imaging Sensor/GLM and wintertime oceanic superbolts observed by the PDD occur in otherwise similar thunderstorm environments. Both are marked by: low storm heights (<10 km), widespread precipitation near the surface, small infrared brightness temperature gradients, and low flash rates. We suggest that the vertically compact, stratiform nature of these clouds provides favorable conditions for superbolt production.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2432311
• Report Number(s): LA-UR--23-24435
• Journal Information: Earth and Space Science, Journal Name: Earth and Space Science Journal Issue: 8 Vol. 10; ISSN 2333-5084
• Publisher: American Geophysical Union (AGU) - WileyCopyright Statement
• Country of Publication: United States
• Language: English