| Summary: | The stability of the West Antarctic Ice Sheet (WAIS) depends on ocean heat transport toward its base and remains a source of uncertainty in sea level rise prediction. The Antarctic Slope Current (ASC), a major boundary current of the ocean's global circulation, serves as a dynamic gateway for heat transport toward Antarctica. Here, we use observations collected from the Bellingshausen Sea to propose a mechanistic explanation for the initiation of the westwardâ€flowing ASC. Waters modified throughout the Bellingshausen Sea by oceanâ€seaâ€ice and oceanâ€iceâ€shelf interactions are exported to the continental slope in a narrow, topographically steered western boundary current. This focused outflow produces a localized front at the shelf break that supports the emerging ASC. This mechanism emphasizes the importance of buoyancy forcing, integrated over the continental shelf, as opposed to local wind forcing, in the generation mechanism and suggests the potential for remote control of melt rates of WAIS' largest ice shelves. © 2020 American Geophysical Union. Issue Online: 13 August 2020; Version of Record online: 13 August 2020; Manuscript accepted: 15 June 2020; Manuscript revised: 20 May 2020; Manuscript received: 04 March 2020. We acknowledge essential contributions from the captain and crew of the R/V Nathaniel B. Palmer as well as the Antarctic Support Contract staff during NBP19â€01. We thank A. Jenkins and D. Shoosmith for sharing data from the JR165 cruise. Funding for AFT was provided by OPPâ€1644172 and the Packard Foundation. Funding for KS was provided by NSF OPPâ€1643679 and OCEâ€1658479. Data Availability Statement: Data from NBP19â€01 are archived at the National Center for Environmental Information; data from JGR165 are archived at the British Oceanography Data Centre; MEOP data are archived at https://www.meop.net. Data from NBP19â€01 are archived at the National Center for Environmental Information and have the NCEI Accession Number 0210639. Published - 2020GL087802.pdf Supplemental Material - ...
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