Abstract
Abstract. The ice shelves of the West Antarctic Ice Sheet experience basal melting induced by underlying warm, salty Circumpolar Deep Water. Basal meltwater, along with runoff from ice sheets, supplies fresh buoyant water to a circulation feature near the coast, the Antarctic Coastal Current (AACC). The formation, structure, and coherence of the AACC has been well documented along the West Antarctic Peninsula (WAP). Observations from instrumented seals collected in the Bellingshausen Sea offer extensive hydrographic coverage throughout the year, providing evidence of the continuation of the westward flowing AACC from the WAP towards the Amundsen Sea. The observations reported here demonstrate that the coastal boundary current enters the eastern Bellingshausen Sea from the WAP and flows westward along the face of multiple ice shelves, including the westernmost Abbot Ice Shelf. The presence of the AACC in the western Bellingshausen Sea has implications for the export of water properties into the eastern Amundsen Sea, which we suggest may occur through multiple pathways, either along the coast or along the continental shelf break. The temperature, salinity, and density structure of the current indicates an increase in baroclinic transport as the AACC flows from the east to the west, and as it entrains meltwater from the ice shelves in the Bellingshausen Sea. The AACC acts as a mechanism to transport meltwater out of the Bellingshausen Sea and into the Amundsen and Ross seas, with the potential to impact, respectively, basal melt rates and bottom water formation in these regions.
Highlights
The Antarctic continental slope in West Antarctica, spanning the West Antarctic Peninsula (WAP) to the western Amundsen Sea, is characterized by a shoaling of the subsurface temperature maximum, which allows warm, salty Circumpolar Deep Water (CDW) greater access to the continental shelf
Some of the largest basal melt rates experienced by Antarctic ice shelves occur in the Amundsen and Bellingshausen seas due to the flow of warm CDW towards the coast and into ice shelf cavities (The IMBIE team, 2018; Paolo et al, 2015; Pritchard et al, 2012)
Using hydrographic data collected from seals equipped with CTD-SRDLs, the structure of the coastal circulation in the Bellingshausen Sea and the southern WAP were investigated
Summary
The Antarctic continental slope in West Antarctica, spanning the West Antarctic Peninsula (WAP) to the western Amundsen Sea, is characterized by a shoaling of the subsurface temperature maximum, which allows warm, salty Circumpolar Deep Water (CDW) greater access to the continental shelf. This leads to an increase in the oceanic heat content over the shelf in this region compared to other Antarctic shelf seas (Schmidtko et al, 2014). Over the continental shelf itself, a major circulation feature is the Antarctic Coastal Current (AACC), which flows westward along the coast of the Antarctic
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