Jupiter’s Great Red Spot, the largest windstorm in the solar system, has been shrinking for decades. A new study might explain why this iconic storm is getting smaller.
The Great Red Spot, located in Jupiter’s southern hemisphere, is a massive, swirling oval of high pressure, more than 10,000 miles wide.
It spins counterclockwise at over 200 miles per hour, making it an anticyclone. For the past 100 years, and especially over the last 50 years, the spot has been shrinking.
While its height has remained relatively constant, its width has decreased significantly. In the late 1800s, it spanned 40 degrees of longitude, but by 2016, when NASA’s Juno spacecraft began orbiting Jupiter, it had shrunk to just 14 degrees.
Caleb Keaveney, a Ph.D. student at Yale’s Graduate School of Arts and Sciences and the lead author of the study published in the journal Icarus, has always been fascinated by the Great Red Spot.
He points out that many people who have studied it over the past 200 years were not professional astronomers but rather passionate and curious individuals.
This shared curiosity connects Keaveney to a broader community interested in unraveling the mysteries of the Great Red Spot, such as when and why it formed and why it is red.
Keaveney, along with co-authors Gary Lackmann from North Carolina State University and Timothy Dowling from the University of Louisville, investigated the impact of smaller, temporary storms on the Great Red Spot.
They used a 3D atmospheric model called the Explicit Planetary Isentropic-Coordinate (EPIC) model, developed by Dowling in the 1990s.
Their simulations included interactions between the Great Red Spot and smaller storms of varying sizes and intensities, as well as control simulations without these smaller storms.
The simulations revealed that the presence of smaller storms actually strengthens the Great Red Spot, causing it to grow larger. “We found through numerical simulations that by feeding the Great Red Spot a diet of smaller storms, as has been known to occur on Jupiter, we could modulate its size,” Keaveney explained.
The researchers based some of their modeling on long-lived high-pressure systems observed on Earth, known as “heat domes” or “blocks.” These systems occur regularly in Earth’s mid-latitudes and play a significant role in extreme weather events like heat waves and droughts.
The longevity of these blocks is linked to interactions with smaller weather systems, such as high-pressure eddies and anticyclones.
“Our study has compelling implications for weather events on Earth,” Keaveney said. “Interactions with nearby weather systems have been shown to sustain and amplify heat domes, which motivated our hypothesis that similar interactions on Jupiter could sustain the Great Red Spot.
In validating that hypothesis, we provide additional support to this understanding of heat domes on Earth.”
Keaveney hopes that further modeling will refine these findings and perhaps shed light on the Great Red Spot’s initial formation. This research not only helps us understand Jupiter’s famous storm better but also offers insights into weather patterns on our own planet.
Source: Yale University.
