April 22, 2022 at 10:30am CST
Speaker: Daphné Lemasquerier, Postdoctoral Fellow, University of Texas Institute for Geophysics
Host: Krista Soderlund
Title: Modeling the large-scale dynamics of Jupiter: vortices and zonal jets
Abstract: The ongoing NASA’s Juno mission is providing stunning observations of Jupiter, which underline the complex fluid dynamics involved in the gas giant. Among others, Jupiter’s atmosphere exhibits multiple persistent vortices embedded within strong zonal jets, both features being part of an intense turbulent flow. I will present laboratory experiments complemented by numerical and theoretical analyses to better understand the emergence and properties of Jovian vortices and zonal jets.
First, I will focus on large-scale Jovian vortices and I will show that based on their quasi-equilibrium state, we can predict the vertical extent of midlatitude anticyclones. We find that they are shallow structures, confined near the weather layer, as recently confirmed by the Juno data, and we predict that the Great Red Spot thickness has remained constant despite its horizontal shrinkage.
Second, I will focus on the strong and deep east-west winds responsible for the banded aspect of Jupiter, the so-called zonal jets. We designed a setup where dominant zonal jets emerge spontaneously from a rapidly rotating turbulent flow with a topographic beta-effect. Our experiments demonstrate the essential role of Rossby waves in the emergence and nonlinear saturation of the jets, and we study the properties of the associated turbulent flow in the so-called zonostrophic regime, relevant to the gas giants.
Because the physical effects involved are not exclusive to Jupiter, our results aim to be generic and applicable to other fluid systems subject to analogous physical effects, such as oceans, atmospheres, and planetary liquid cores.