Dynamic Europa ocean shows transient Taylor columns and convection driven by ice melting and salinity

TL;DR

This study models Europa's ocean dynamics, revealing transient convection, Taylor columns, and salinity-driven stratification, with implications for ice thickness and potential habitability.

Contribution

It introduces a comprehensive model including ice melting effects, showing complex transient convection and Taylor columns in Europa's ocean.

Findings

Transient convection and eddies dominate ocean dynamics.

Taylor columns form parallel to Europa's rotation axis.

Ocean heat transport leads to nearly uniform ice thickness.

Abstract

The deep (~100 km) ocean of Europa, Jupiter's moon, covered by a thick icy shell, is one of the most probable places in the solar system to find extraterrestrial life. Yet, its ocean dynamics and its interaction with the ice cover have received little attention. Previous studies suggested that Europa's ocean is turbulent using a global model and taking into account non-hydrostatic effects and the full Coriolis force. Here we add critical elements, including consistent top and bottom heating boundary conditions and the effects of icy shell melting and freezing on ocean salinity. We find weak stratification that is dominated by salinity variations. The ocean exhibits strong transient convection, eddies, and zonal jets. Transient motions organize in Taylor columns parallel to Europa's axis of rotation, are static outside of the tangent cylinder and propagate equatorward within the cylinder. The meridional oceanic heat transport is intense enough to result in a nearly uniform ice thickness, that is expected to be observable in future missions.