English

The range of Jupiter's flow structures fitting the Juno asymmetric gravity measurements

Earth and Planetary Astrophysics 2020-09-02 v2

Abstract

The asymmetric gravity field measured by the Juno spacecraft allowed estimation of the depth of Jupiter's zonal jets, showing that the winds extend approximately 30003000 km beneath the cloud-level. This estimate was based on an analysis using a combination of all measured odd gravity harmonics J3J_{3}, J5J_{5}, J7J_{7}, and J9J_{9}, but the wind profile dependence on each of them separately has not been investigated. Furthermore, these calculations assumed the meridional profile of the cloud-level wind extends to depth. However, it is possible that the interior jet profile varies from that of the cloud-level as hinted by the Juno microwave measurement that find a smoother nadir brightness temperature profile at depth compared to the cloud-level. Here we analyze in detail the possible meridional and vertical structure of Jupiter's deep jet-streams. We find that each odd gravity harmonic constrains the flow at a different depth, with J3J_{3} being the most dominant at depths below 30003000 km, J5J_{5} being the most restrictive overall, and J9J_{9} not constraining the flow at all if the other odd harmonics are within the measurement range. Interior flow profiles constructed from perturbations to the cloud-level winds allow a more extensive range of vertical wind profiles, yet when the profiles differ substantially from the cloud-level, the ability to match the gravity data reduces significantly. Overall, we find that while interior wind profiles that do not resemble the cloud-level are possible, they are statistically unlikely. However, slightly smoother profiles, which resemble the Juno's microwave radiometer temperature profile at depth, are still compatible with the gravity measurements.

Keywords

Cite

@article{arxiv.2005.01295,
  title  = {The range of Jupiter's flow structures fitting the Juno asymmetric gravity measurements},
  author = {Keren Duer and Eli Galanti and Yohai Kaspi},
  journal= {arXiv preprint arXiv:2005.01295},
  year   = {2020}
}

Comments

17 pages, 8 figures, In review (JGR planets)