Pathways of ocean heat towards Pine Island and Thwaites grounding lines

In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high ice shelf melting near the ice sheet grounding lines, accelerating ice flow, and controlling the pace of future Antarctic contributions to global sea level. The pathways of mCDW towards groundi...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Nakayama, Yoshihiro, Manucharyan, Georgy, Zhang, Hong, Dutrieux, Pierre, Torres, Hector S., Klein, Patrice, Seroussi, Helene, Schodlok, Michael, Rignot, Eric, Menemenlis, Dimitris
Format: Article in Journal/Newspaper
Language:English
Published: Nature Publishing Group 2019
Subjects:
Amundsen Sea
Antarctic
Austral
Antarc*
Ice Sheet
Ice Shelf
Online Access:https://authors.library.caltech.edu/100164/
https://authors.library.caltech.edu/100164/1/s41598-019-53190-6.pdf
https://authors.library.caltech.edu/100164/2/41598_2019_53190_MOESM1_ESM.pdf
https://resolver.caltech.edu/CaltechAUTHORS:20191203-105900453
Description
Summary:In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high ice shelf melting near the ice sheet grounding lines, accelerating ice flow, and controlling the pace of future Antarctic contributions to global sea level. The pathways of mCDW towards grounding lines are crucial as they directly control the heat reaching the ice. A realistic representation of mCDW circulation, however, remains challenging due to the sparsity of in-situ observations and the difficulty of ocean models to reproduce the available observations. In this study, we use an unprecedentedly high-resolution (200 m horizontal and 10 m vertical grid spacing) ocean model that resolves shelf-sea and sub-ice-shelf environments in qualitative agreement with existing observations during austral summer conditions. We demonstrate that the waters reaching the Pine Island and Thwaites grounding lines follow specific, topographically-constrained routes, all passing through a relatively small area located around 104°W and 74.3°S. The temporal and spatial variabilities of ice shelf melt rates are dominantly controlled by the sub-ice shelf ocean current. Our findings highlight the importance of accurate and high-resolution ocean bathymetry and subglacial topography for determining mCDW pathways and ice shelf melt rates.

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