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A pole-to-equator ocean overturning circulation on Enceladus

Lobo, Ana H. and Thompson, Andrew F. and Vance, Steven D. and Tharimena, Saikiran (2020) A pole-to-equator ocean overturning circulation on Enceladus. . (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20200901-084534440

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Abstract

Enceladus is believed to have a saltwater global ocean with a mean depth of at least 30~km, heated from below at the ocean-core interface and cooled at the top, where the ocean loses heat to the icy lithosphere above. This scenario suggests an important role for vertical convection to influence the interior properties and circulation of Enceladus' ocean. Additionally, the ice shell that encompasses the ocean has dramatic meridional thickness variations that, in steady state, must be sustained against processes acting to remove these ice thickness anomalies. One mechanism that would maintain variations in the ice shell thickness involves spatially-separated regions of freezing and melting at the ocean-ice interface. Here, we use an idealized, dynamical ocean model forced by an observationally-guided density forcing at the ocean-ice interface to argue that Enceladus' interior ocean should support a meridional overturning circulation. This circulation establishes an interior density structure that is more complex than in studies that have focused only on convection, including a shallow freshwater lens in the polar regions. Spatially-separated sites of ice formation and melt enable Enceladus to sustain a significant vertical and horizontal stratification, which impacts interior heat transport, and is critical for understanding the relationship between a global ocean and the planetary energy budget. The presence of low salinity layers near the polar ocean-ice interface also influences whether samples measured from the plumes are representative of the global ocean.


Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/2007.06173arXivDiscussion Paper
ORCID:
AuthorORCID
Thompson, Andrew F.0000-0003-0322-4811
Vance, Steven D.0000-0002-4242-3293
Additional Information:A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). This work was partially supported by JPL's strategic research and technology program, and by the Icy Worlds node of NASA's Astrobiology Institute (13-13NAI7 2-0024). © 2020. All rights reserved. AFT was supported by the David and Lucile Packard Foundation.
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
NASA80NM0018D0004
NASA13-13NAI7 2-0024
David and Lucile Packard FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:20200901-084534440
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200901-084534440
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105191
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 19:24
Last Modified:08 Sep 2020 19:24

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