A mysterious weather anomaly on Venus has finally been explained in new research, providing deeper insights into the weather volatility of other planets in our solar system.
University of Tokyo researchers revealed their findings in a recent paper published in the Journal of Geophysical Research, focused on their investigation of a massive cloud disturbance observed on the second planet from the Sun.
This unusual cloud phenomenon involves a 6,000-kilometer-wide wave front that travels around Venus over just a few Earth days, and scientists believe it could potentially affect future space missions.
A Weather Aberration on Venus
Japan’s Akatsuki Venus orbiter first observed Venus’s enormous, 6,000-kilometer-wide atmospheric wave move across the planet’s equator at tremendous speed in 2016. Now, a decade later, the University of Tokyo team has some answers about this peculiar feature.
Compared to Earth, Venus is a slow mover, with its rotation even slower than its 243-day orbit. Despite this, Venusian clouds move at an incredible pace, 60 times the planet’s rotational speed in what is known as “superrotation,” a phenomenon also observed on Mars, the Sun, and Earth’s supersonic atmosphere.
“We identified the phenomena, but for years we couldn’t understand it,” said lead author Professor Takeshi Imamura from the Graduate School of Frontier Sciences at the University of Tokyo. “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.”
A Natural Weather Lab
The Venusian atmosphere is hot, dense, and toxic, being composed of almost 97% carbon dioxide. This results in constant cloud cover, which rains sulfuric acid. While this creates a deadly environment for humans, at a distance, it’s a perfect natural weather laboratory. This extreme cloud density makes hard-to-spot weather patterns and processes more readily apparent than they would be on a planet such as ours.
The strange formation in the Venusian atmosphere resulted from a sudden slowdown of the fluid, known as a hydraulic jump, produced when a large atmospheric Kelvin wave moving east across Venus becomes unstable in the lower to middle cloud region. The Kelvin wave’s sudden slowing produces an updraft, pushing sulfuric acid vapor into the upper atmosphere, where it can condense into clouds. As though clouds trail, they form the enormous wavefront spotted by Akatsuki Venus.
“Venus has three distinct cloud layers, and the dynamics of the lower and middle layers are not so well understood,” said Imamura. “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.”
Analyzing Venusian Weather
The Japanese researchers used a fluid-dynamic model to simulate the hydraulic jump observed on Venus, combined with a microphysical box model to track air flow through the atmosphere. In their analysis, the University of Tokyo researchers identified how the cloud disturbance maintains the Venusian atmosphere’s superrotation.
“Up until now, we used a global circulation model (GCM) for Venus that is similar to Earth’s, but this model doesn’t include the hydraulic jump which we have now identified,” explained Imamura. “Our next step will be to test this discovery within a more inclusive climate model that includes other atmospheric processes. We will face challenges due to the significant processing power required to run such simulations. Even with modern supercomputers, it isn’t easy.”
This marks the first hydraulic jump observed on another planet, but the researchers say this may be a portent of things to come as scientists get a closer look at other bodies in the universe.
“Under some circumstances, Mars’ atmosphere may also have the right conditions for a hydraulic jump,” mentioned Imamura.
As humanity stretches out into space with hopes of crewed Mars landings in the coming decades, advancing models of extraterrestrial atmospheric conditions will be essential to mission safety.
The paper, “A Planetary-Scale Hydraulic Jump Driving Venus’ Cloud Front,” appeared in the Journal of Geophysical Research on April 24, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.