The Center for Atmospheric Sciences | » Analysis of planetary waves in Saturn’s 42°N atmospheric jet

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  • Analysis of planetary waves in Saturn’s 42°N atmospheric jet

    During their 1980 and 1981 flybys of Saturn, the Voyager spacecraft imaged a dark, sinuous line encircling the planet. This feature, dubbed the ribbon wave after its visual appearance, was embedded in an atmospheric jet stream at 42°N latitude. The Cassini spacecraft also discovered waves in the 42°N jet during its 2004–2017 Saturn mission. Using images taken by Cassini, we have identified the ribbon waves as Rossby waves, that is, planet‐scale waves that are common in atmospheres, including that of the Earth. Unlike Earth’s atmospheric Rossby waves, which are only visible as undulations on weather maps, Saturn’s ribbons are visually striking and may be some of the most prominent examples of Rossby waves in the Solar System. The ribbons are composed of a number of wavelengths, each of which is affected differently by the atmosphere and move at different speeds. By measuring the differing speed of these wavelength components, we compared the behavior of the ribbons to theoretical predictions for Rossby waves and estimated basic properties of the atmosphere. Because the ribbons likely extend deep into the atmosphere, they may help shed light on the how the atmosphere behaves at depths that Cassini was not able to observe directly.

    This research was published in Geophysical Research Letters.