Enceladus

The Effect Of Salinity On Ocean Circulation And Ice-ocean Interaction On Enceladus

By Keith Cowing
Status Report
astro-ph.EP
June 16, 2023
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The Effect Of Salinity On Ocean Circulation And Ice-ocean Interaction On Enceladus
Zonal-mean temperature (T, a), salinity anomaly (S, b), and potential density anomaly (ρσ, with reference pressure near the ocean surface, c) in the quasi-equilibrium state of all simulations. The first to the fourth columns are results of the high salinity simulation with high horizontal diffusivity (HSh), high salinity simulation with low horizontal diffusivity (HSl), low salinity simulation with high horizontal diffusivity (LSh), and low salinity simulation with low horizontal diffusivity (LSl), respectively. In (a1) & (a2), the contour interval is 0.01 ◦C below -2.14 ◦C and 0.001 ◦C above -2.14 ◦C. In (a3) & (a4), the contour interval is 0.01 ◦C below -0.6 ◦C and 0.2 ◦C above -0.6 ◦C. In (b1) & (b2), a reference salinity of 34.97 g kg−1 is subtracted, and the contour interval is 10−3 g kg−1 . In (b3) & (b4), a reference salinity of 8.45 g kg−1 is subtracted, and the contour interval is 5×10−4 g kg−1 . In (c1) & (c2), a reference density of 1029.13 kg m−3 is subtracted, and the contour interval is 10−3 kg m−3 below 5 × 10−3 kg m−3 and 3 × 10−4 kg m−3 above 5×10−3 kg m−3 . In (c3) & (c4), a reference density of 1007.7 kg m−3 is subtracted, and the contour interval is 10−3 kg m−3 below -10−2 kg m−3 and 5 × 10−3 kg m−3 above -10−2 kg m−3 — astro-ph.EP

Observational data suggest that the ice shell on Enceladus is thicker at the equator than at the pole, indicating an equator-to-pole ice flow.

If the ice shell is in an equilibrium state, the mass transport of the ice flow must be balanced by the freezing and melting of the ice shell, which in turn is modulated by the ocean heat transport. Here we use a numerical ocean model to study the ice-ocean interaction and ocean circulation on Enceladus with different salinities.

We find that salinity fundamentally determines the ocean stratification. A stratified layer forms in the low salinity ocean, affecting the ocean circulation and heat transport. However, in the absence of tidal heating in the ice shell, the ocean heat transport is found to always be equatorward, resulting in freezing at the pole and melting at lower latitudes, which cannot maintain the ice shell geometry against the equator-to-pole ice flow.

The simulation results suggest that either the ice shell on Enceladus is not in an equilibrium state, or tidal dissipation in the ice shell is important in maintaining the ice shell geometry.

Yaoxuan Zeng, Malte F. Jansen

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2306.08603 [astro-ph.EP] (or arXiv:2306.08603v1 [astro-ph.EP] for this version)
Submission history
From: Yaoxuan Zeng
[v1] Wed, 14 Jun 2023 16:07:50 UTC (3,756 KB)
https://arxiv.org/abs/2306.08603
Astrobiology

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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