[Houghton – PAOCQ] Yohai Kaspi (Weizmann Institute) – The atmospheric dynamics of Jupiter, Part I: the circumpolar cyclones

This is the first 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 first broadly introduce the Juno mission and then focus on the dynamics of the polar regions, which were revealed by Juno due to its unique polar orbit. While equatorward of latitude 65 the atmosphere is dominated by east-west jet streams, poleward of this latitude (where the Rhines scale becomes large), the atmosphere is dominated by a “sea” of cyclonic and anticyclonic features. Particularly, the Juno mission revealed that both poles of Jupiter contain coherent large-scale polar cyclones surrounded by a ring of similar sized circumpolar cyclones (CPCs). These spectacular cyclones appear in a “crystal-like” structure and have been stable for the past 9 years. The north pole holds eight such CPCs and the south pole possesses five, with both circumpolar rings positioned along latitude ~84° N/S. By establishing the primary forces that act on the CPCs we explain in this talk the particular latitudinal location, stability and number of the Jovian CPCs. Moreover, following the CPCs over time, using data accumulated throughout the Juno mission, and analyzing the forces acting on them due to the planetary spin and interaction between the CPCs over time, we explain also their westward drift and oscillatory behavior. Finally, using the westward drift rate we put constraints on the possible depth of the cyclones and compare to recent depth-dependent microwave measurements by Juno.

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