Direct observations of melting, freezing, and ocean circulation in an ice shelf basal crevasse

Ocean conditions near the grounding zones of Antarctica’s ice shelves play a key role in controlling the outflow and mass balance of the ice sheet. However, ocean observations in these regions are largely absent. Here, we present a detailed spatial survey collected with an underwater vehicle in a ba...

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Bibliographic Details
Published in:Science Advances
Main Authors: Washam, Peter, Lawrence, Justin D., Stevens, Craig L., Hulbe, Christina L., Horgan, Huw J., Robinson, Natalie J., Stewart, Craig L., Spears, Anthony, Quartini, Enrica, Hurwitz, Benjamin, Meister, Matthew R., Mullen, Andrew D., Dichek, Daniel J., Bryson, Frances, Schmidt, Britney E.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2023
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Online Access:http://dx.doi.org/10.1126/sciadv.adi7638
https://www.science.org/doi/pdf/10.1126/sciadv.adi7638
Description
Summary:Ocean conditions near the grounding zones of Antarctica’s ice shelves play a key role in controlling the outflow and mass balance of the ice sheet. However, ocean observations in these regions are largely absent. Here, we present a detailed spatial survey collected with an underwater vehicle in a basal crevasse located in the ocean cavity at the Ross Ice Shelf grounding zone. The observations depict fine-scale variability in ocean forcing that drives asymmetric melting along the lower crevasse sidewalls and freezing in the upper reaches of the crevasse. Freshwater release from melting at depth and salt rejection from freezing above drives an overturning circulation. This vertical circulation pattern overlays a dominant throughflow jet, which funnels water parallel to the coastline, orthogonal to the direction of tidal currents. Importantly, these data reveal that basal crevasses influence ocean circulation and mixing at ice shelf grounding zones to an extent previously unknown.