The vertical structure of Jupiter's equatorial zonal wind above the cloud deck, derived using mesoscale gravity waves

TL;DR

This study derives Jupiter's equatorial zonal wind profile above the cloud deck using mesoscale gravity waves from Galileo Probe data, revealing wind acceleration, the turbopause location, and a possible cross-equatorial jet oscillation.

Contribution

It introduces a novel method of using gravity wave Lomb-Scargle periodograms to map Jupiter's vertical wind structure from in-situ data.

Findings

Wind speed increases with altitude up to ~150 m/s

Identification of the turbopause as a wide wave spectrum region

Evidence for a cross-equatorial jet oscillation

Abstract

Data from the Galileo Probe, collected during its descent into Jupiter's atmosphere, is used to obtain a vertical profile of the zonal wind from $\mathbf{\sim 0.5}$ bar (upper troposphere) to $\mathbf{\sim 0.1\, \mu{bar}}$ (lower thermosphere) at the probe entry site. This is accomplished by constructing a map of gravity wave Lomb-Scargle periodograms as a function of altitude. The profile obtained from the map indicates that the wind speed above the visible cloud deck increases with height to $\mathbf{\sim 150}$ m\,s$\mathbf{^{-1}}$ and then levels off at this value over a broad altitude range. The location of the turbopause, as a region of wide wave spectrum, is also identified from the map. In addition, a cross-equatorial oscillation of a jet, which has previously been linked to the quasi-quadrennial oscillation in the stratosphere, is suggested by the profile.