Winter thermohaline evolution along and below the Ross Ice Shelf

Pierpaolo Falco; Naomi Krauzig; Pasquale Castagno; Angela Garzia; Riccardo Martellucci; Yuri Cotroneo; Daniela Flocco; Milena Menna; Annunziata Pirro; Elena Mauri; Francesco Memmola; Cosimo Solidoro; Massimo Pacciaroni; Giulio Notarstefano; Giorgio Budillon; Enrico Zambianchi

doi:10.1038/s41467-024-54751-8

What is it about?

This study explores the intricate interactions between the ocean and ice in Antarctica's Ross Ice Shelf, the largest ice shelf on Earth. Over three years (2020–2023), we used specially programmed Argo floats to collect year-round observations along the ice shelf front and within its cavity. Our research focuses on key thermohaline processes, including the formation of High Salinity Shelf Water (HSSW) and the intrusion of Antarctic Surface Water (ASW). These processes drive frontal and basal melting, significantly influencing the global climate system.

Photo by Birger Strahl on Unsplash

Why is it important?

The Ross Ice Shelf plays a critical role in regulating ocean circulation and global climate. Understanding its thermohaline dynamics is essential for predicting how Antarctic ice shelves will respond to and influence climate change. This study provides the first direct year-round measurements of: -HSSW production (a precursor to Antarctic Bottom Water, which drives global ocean circulation). -ASW intrusions (the key driver of melting at the ice shelf base and front). -Ocean heat content and basal melt rates beneath the ice shelf, offering new insights into ice shelf-ocean interactions. These findings not only validate previously hypothesized processes but could also help refine models of ice shelf behavior and their contributions to sea level rise.

Perspectives

This paper feels special because it represents a leap in our understanding of the Ross Ice Shelf's winter dynamics. As someone deeply invested in going beyond traditional observational approaches, being able to capture year-round processed using autonomous instruments under ice is an incredible achievement. I also especially feel gracious for being part of one of the only teams in polar seas that undertakes the challenging task of recovering and redeploying these unconventionally programmed Argo floats.
Naomi Krauzig
Universita degli Studi di Napoli Parthenope

This page is a summary of: Winter thermohaline evolution along and below the Ross Ice Shelf, Nature Communications, December 2024, Springer Science + Business Media,
DOI: 10.1038/s41467-024-54751-8.
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Winter thermohaline evolution along and below the Ross Ice Shelf
Abstract The Ross Ice Shelf floats above the southern sector of the Ross Sea and creates a cavity where critical ocean-ice interactions take place. Crucial processes occurring in this cavity include the formation of Ice Shelf Water, the coldest ocean water, and the intrusion of Antarctic Surface Water, the main driver of frontal and basal melting. During the winter, a polynya forms along the Ross Ice Shelf edge, producing a precursor to Antarctic Bottom Water known as High Salinity Shelf Water. Due to the difficulty of direct exploration of the Ross Ice Shelf in the winter, processes occurring there have been only hypothesized to date. Here we show thermohaline observations collected along the Ross Ice Shelf front from 2020 to 2023 using unconventionally programmed Argo floats. These measurements provide year-round observations of water column changes in and around the Ross Ice Shelf cavity, allowing to quantify production of High Salinity Shelf Water, ocean heat content and basal melt rates.

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Naomi Krauzig
Universita degli Studi di Napoli Parthenope

Winter dynamics along and beneath the Ross Ice Shelf from unconventionally programmed Argo floats

What is it about?

Why is it important?

Perspectives

Resources