On-shelf circulation of warm water toward the Totten Ice Shelf in East Antarctica

• Published in: Nature Communications
• Main Authors: Daisuke Hirano, Takeshi Tamura, Kazuya Kusahara, Masakazu Fujii, Kaihe Yamazaki, Yoshihiro Nakayama, Kazuya Ono, Takuya Itaki, Yuichi Aoyama, Daisuke Simizu, Kohei Mizobata, Kay I. Ohshima, Yoshifumi Nogi, Stephen R. Rintoul, Esmee van Wijk, Jamin S. Greenbaum, Donald D. Blankenship, Koji Saito, Shigeru Aoki
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Science; Q; East Antarctica; Totten Glacier; Antarc*; Antarctica; Ice Shelf; Totten Ice Shelf
• Online Access: https://doi.org/10.1038/s41467-023-39764-z; https://doaj.org/article/c79ba67253354d47a0ff9cc2ae3fa015

Abstract The Totten Glacier in East Antarctica, with an ice volume equivalent to >3.5 m of global sea-level rise, is grounded below sea level and, therefore, vulnerable to ocean forcing. Here, we use bathymetric and oceanographic observations from previously unsampled parts of the Totten continental shelf to reveal on-shelf warm water pathways defined by deep topographic features. Access of warm water to the Totten Ice Shelf (TIS) cavity is facilitated by a deep shelf break, a broad and deep depression on the shelf, a cyclonic circulation that carries warm water to the inner shelf, and deep troughs that provide direct access to the TIS cavity. The temperature of the warmest water reaching the TIS cavity varies by ~0.8 °C on an interannual timescale. Numerical simulations constrained by the updated bathymetry demonstrate that the deep troughs play a critical role in regulating ocean heat transport to the TIS cavity and the subsequent basal melt of the ice shelf.