2026-03-23 カリフォルニア大学バークレー校(UCB)
NASA’s Juno spacecraft passed north-to-south (yellow track) over Jupiter’s atmosphere on August 17, 2022, detecting a cluster of radio pulses from lightning (cyan symbols marking instrument pointing for each pulse). A background map from the Hubble Space Telescope identified the lightning source as an isolated “stealth superstorm.”Michael Wong et al. (2026, AGU Advances; HST and Juno MWR)
＜関連情報＞
- https://news.berkeley.edu/2026/03/23/lightning-bolts-on-jupiter-pack-more-than-100-times-the-power-of-earths-flashes/
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025AV002083
木星の2021～2022年のステルス型巨大嵐における雷の電波パルス電力分布 Radio Pulse Power Distribution of Lightning in Jupiter’s 2021–2022 Stealth Superstorms
Michael H. Wong, Ivana Kolmašová, Fabiano A. Oyafuso, Masafumi Imai, Shinji Mizumoto, Steven M. Levin, Ramanakumar G. Sankar, Amy A. Simon, Shawn Brueshaber,…
AGU Advances Published: 20 March 2026
DOI:https://doi.org/10.1029/2025AV002083
Abstract
Surveys and observations of lightning on Jupiter prior to the NASA Juno mission used night-side imaging approaches, and a common conclusion was that the optical energy was similar to the highest energy terrestrial lightning flashes, or superbolts. We use data from the Juno Microwave Radiometer (MWR) to measure the first radio pulse power distribution of Jovian lightning. The power distribution measurement was enabled by unique meteorological conditions in Jupiter’s North Equatorial Belt (NEB) in 2021–2022, as the belt transitioned from an anomalously quiescent (non-convective) state to its more typical configuration with small moist convective plumes scattered in longitude. During this transition, convective plumes in the NEB occurred only in isolated storms we label “stealth superstorms.” The isolated nature of these storms (as lightning sources) resolved the degeneracy between pulse location and pulse strength, allowing measurement of a pulse power distribution with statistical median values ranging from 27 to 214 W over the MWR bandpass, well within the observational sensitivity range. The MWR thus measures typical pulse power in the storms, rather than high-power outliers. Pulse power in the stealth superstorms may be comparable to terrestrial lightning radio emission, or up to a million times more powerful, depending on uncertainties in unresolved pulse duration and lightning spectral energy distributions. Future studies may determine whether the lightning pulse power in stealth superstorm is typical or anomalous of Jupiter’s lightning in general.
Plain Language Summary
Most previous Jupiter lightning measurements used night-side imaging, commonly concluding that the optical energy of Jupiter’s lightning flashes was similar to the highest-energy lightning flashes on Earth, known as “superbolts.” We find that the power of lightning flashes at radio wavelengths could be similar to the power of Earth lightning. However, there is significant uncertainty about how long pulses really last, or how power changes at different wavelengths, so our measurements could be up to a million times stronger. We used data from the Juno mission’s Microwave Radiometer (MWR) instrument. A unique pattern of activity in 2021–2022 followed an unusually calm and quiet state in a specific region on Jupiter. The unique pattern featured “stealth superstorms” with no other storms nearby. Lightning power detected by MWR is affected by both source power and source location, but with isolated stealth superstorms, we were able to disentangle these two effects for the first time. We analyzed the power of all the detected pulses, finding a histogram shape that includes a clear peak, rather than a decreasing tail. The signals therefore come from typical lightning pulses, rather than only the highest-power superbolts in the histogram.
