Venus has long fascinated scientists with its thick clouds, extreme heat, and mysterious weather systems. But a new discovery, published in the Journal of Geophysical Research: Planets, has brought us closer to understanding one of the planet’s most enigmatic atmospheric phenomena: a colossal 6,000-kilometer-wide wave that circulates around Venus’ equator. This wave, scientists now know, is the result of the largest hydraulic jump ever observed in the solar system.
For years, the origin of this strange atmospheric wave had puzzled scientists. But after careful modeling and research by a team led by the University of Tokyo’s Professor Takeshi Imamura, the mystery has been solved.
Understanding Hydraulic Jumps: The Key to the Discovery
In the simplest terms, a hydraulic jump is a sudden shift in the flow of a fluid, where it slows down and deepens. A familiar example is the way water from a tap behaves when it hits a sink: it starts as a fast-moving stream but suddenly spreads out into a wider, slower flow. On Venus, the hydraulic jump works in a similar way. The atmospheric wave, moving eastward through the lower cloud layers, reaches a critical point where its flow becomes unstable. As wind speeds rapidly slow down, a strong vertical updraft is generated, which carries sulfuric acid vapor high into the atmosphere.
The resulting cloud formation follows behind this updraft, creating the enormous atmospheric wave seen on Venus. This phenomenon, described as an enormous hydraulic jump, had never before been identified on any other planet.
Professor Imamura explains,
“We identified the phenomena, but for years we couldn’t understand it. However, thanks to this research, we’re now able to show that this cloud disruption is caused by the largest known hydraulic jump in the solar system.”
These images taken on Aug. 18 (left) and Aug. 27 (right), 2016, by the near-infrared camera on Japan’s Akatsuki Venus probe, show the clear line of denser (darker) clouds moving across the planet.
Credit: Journal of Geophysical Research: Planets (2026). DOI: 10.1029/2026je009672
New Model of Venus’ Cloud Dynamics
Prior to this study, scientists relied on global circulation models (GCM) that simulated Venus’ weather based on similar models for Earth. However, these models did not account for the hydraulic jump identified in this new research. By using advanced fluid dynamics simulations and microphysical box models, the team demonstrated how the hydraulic jump is integral to understanding Venus’ cloud formation.
The study published in the Journal of Geophysical Research: Planets, also helps explain why Venus’ atmosphere exhibits superrotation, where winds move 60 times faster than the planet itself. This phenomenon had puzzled scientists for years, but the new research suggests that the wave induced by the hydraulic jump might play a key role in maintaining superrotation.
As Imamura puts it,
“Venus has three distinct cloud layers, and the dynamics of the lower and middle layers are not so well understood. Our discovery of a hydraulic jump on Venus connecting a very large-scale horizontal process with a strong localized vertical wave is unexpected, as in fluid dynamics these are usually disconnected.”
Hydraulic jump simulation. This cross section of the Venusian atmosphere shows a numerical simulation of a hydraulic jump in action. The color indicates the “potential temperature,” which represents the atmospheric material surface. The jump appears as a stepwise transition of the material surface.
©T. Imamura, Y. Maejima, K. Sugiyama et al., 2026 CC-BY
Looking Ahead: Challenges and Future Research
With the hydraulic jump now identified, the next steps for the team involve refining their model to incorporate a broader range of atmospheric processes. This will require much more computational power, as the simulations are complex and require supercomputers to process. Despite these challenges, Imamura remains optimistic about the future.
“Our next step will be to test this discovery within a more inclusive climate model that includes other atmospheric processes. We will face some challenges due to the huge amount of processing power required to run such simulations. Even with modern supercomputers, it isn’t easy,” said Imamura.
This discovery also opens the door for further research on other planets, particularly Mars. As Imamura notes, “Under some circumstances, Mars’ atmosphere may also have the right conditions for a hydraulic jump.” This raises the possibility that future Mars missions might benefit from understanding how similar phenomena could occur on the Red Planet.