Jupiter's equatorial quasi-quadrennial oscillation forced by internal thermal forcing

TL;DR

This study demonstrates that internal thermal disturbances in a Jupiter model can generate equatorial quasi-quadrennial oscillations and multiple jet streams, revealing the wave mechanisms behind Jupiter's observed atmospheric variability.

Contribution

It introduces a simulation approach showing how internal thermal forcing excites waves that produce Jupiter's QQO and jet streams, advancing understanding of planetary atmospheric dynamics.

Findings

Thermal disturbances excite waves that generate QQO-like oscillations.

The dominant wave mode has a zonal wavenumber of 10.

Off-equatorial jets migrate and strengthen equatorial jets, prolonging oscillations.

Abstract

Observations have shown that there exists downward propagation of alternating westward/eastward jets in Jupiter's equatorial stratosphere, with a quasi-period between four and six years. This phenomenon is generally called the quasi-quadrennial oscillation (QQO). Here, we simulate the QQO by injecting isotropic small-scale thermal disturbances into a three-dimensional general circulation model of Jupiter. It is found that the internal thermal disturbance is able to excite a wealth of waves that generate the equatorial QQO and multiple jet streams at middle and high latitudes of both hemispheres. The dominant wave mode in generating the QQO-like oscillation is that with a zonal wavenumber of 10. Inhomogeneous evolution of potential vorticity favors the emergence of the off-equatorial zonal jets. The off-equatorial jets migrate to the equator, strengthen the deep equatorial jets, and result in the prolonging of the QQO-like oscillations.