Jupiter’s atmospheric jet streams extend thousands of kilometres deep

Abstract

The depth to which Jupiter's observed east-west jet streams extend has been a long-standing question. Resolving this puzzle has been a primary goal for the Juno spacecraft, which has been in orbit around the gas giant since July 2016. Juno's gravitational measurements have revealed that Jupiter's gravitational field is north-south asymmetric, which is a signature of the planet's atmospheric and interior flows. Here we report that the measured odd gravitational harmonics J, J, J and J indicate that the observed jet streams, as they appear at the cloud level, extend down to depths of thousands of kilometres beneath the cloud level, probably to the region of magnetic dissipation at a depth of about 3,000 kilometres. By inverting the measured gravity values into a wind field, we calculate the most likely vertical profile of the deep atmospheric and interior flow, and the latitudinal dependence of its depth. Furthermore, the even gravity harmonics J and J resulting from this flow profile also match the measurements, when taking into account the contribution of the interior structure. These results indicate that the mass of the dynamical atmosphere is about one per cent of Jupiter's total mass.

Dynamo Action in the Steeply Decaying Conductivity Region of Jupiter‐Like Dynamo Models

“…The authors argue that the spectrum of is close to a white spectrum at this depth, a criterion that successfully predicts Earth's core‐mantle boundary when excluding the axial dipole contribution. However, 0.85 r J lies below the transition to the metallic Hydrogen region (French et al, ) and below the anticipated depth of the zonal winds (Kaspi et al, ). The magnetic Reynolds numbers reached in the simulations are orders of magnitude lower than in Jupiter (Duarte et al, ).…”

Jupiter's Turbulent Power Spectra From Hubble Space Telescope

“…We can explore the regions underneath the clouds utilizing longer wavelength observatories like the National Radio Astronomy Observatory Very Large Array (VLA; Cosentino et al, ; de Pater et al, ) or space based missions like Juno (Bolton et al, ; Kaspi et al, ). In this paper, we studied these regions indirectly by analyzing global maps of Jupiter's atmosphere at optical wavelengths probing the cloud deck.…”

“…A 3‐D turbulent signature would suggest that the winds at the cloud layer are connected to the winds deeper down (Busse, ), but a 2‐D signature might suggest the opposite, that the winds at the cloud layer are shallow and not strongly coupled to the dynamics of the deeper planet (Ingersoll & Cuzzi, ). As new data are being acquired from the Juno mission, these theories may need to be (Bolton et al, ; Kaspi et al, ; Li et al, ).…”

A deeper look at Jupiter

“…On page 242, Santos et al 2 investigate the evolution of cooperation using computer-based modelling analyses, and they identify a rule for moral judgements that provides an especially powerful system to drive cooperation.…”

“…In particular, is the planet's interior as dynamic as its surface? In three papers [1][2][3] in this issue, scientists have used small signatures in the gravitational field of Jupiter to address these questions and to potentially revolutionize our understanding of the internal dynamics of such gas-giant planets.…”