[Houghton Lecture] Yohai Kaspi (Weizmann Institute) – The atmospheric dynamics of Jupiter, Part II: the multiple midlatitude jet-streams and Ferrel cells

This is the second of a series of three talks about Jupiter’s atmospheric dynamics, with a focus on discoveries since the arrival of NASA’s Juno mission to Jupiter in 2016.

In this talk, we will examine the midlatitudes, which host some of the most powerful jet-streams and vortices in the Solar System. Since the first views of Jupiter by Galileo Galilei it was evident that the atmosphere is dominated by east-west bands, yet their origin was unclear. It was later confirmed that these bands are correlated with the engulfing jet-streams, yet still the depth, structure and governing dynamics remained unknown. The Juno mission, equipped with several instruments that allow sensing deep into the atmosphere and interior allowed for the first time to reveal the deep atmospheric dynamics and explain their origin. In this talk, we will show how Juno gravity and magnetic field measurements allow to constrain the depth and vertical structure of the zonal flows. These measurements provide also direct evidence that the flows penetrate inward slantwise, along the direction of the spin axis, confirming the cylindrical nature of the flow, which has been postulated theoretically since the 1970s. Juno microwave measurements show the existence of vertical flow associated with meridional circulation cells, resembling mechanistically terrestrial Ferrel-cells driven by regions of momentum flux-convergence. However, unlike Earth, Jupiter’s rapid rotation and size produce eight such cells per hemisphere, and these are mass-transporting due to the barotropic character of the surrounding jets. Finally, we will discuss Jupiter’s largest storm, the Great Red Spot, and show how combined Juno microwave and gravity data constrain its vertical extent and structure. Generalizing the jet, cell, and vortex dynamics observed on Jupiter provides a broader understanding of the fundamental physics governing atmospheric circulation across planetary environments.

Houghton Lecture Series

Supported by the Houghton Fund, Houghton Lecturers are distinguished visitors from outside MIT, invited by the EAPS Program in Atmospheres, Oceans and Climate (PAOC) to spend a period of time, ranging from a week to several months, as scientists-in-residence.

Contact: kbauer@mit.edu