| Summary: | The marine-terminating glaciers of the Amundsen Sea are experiencing increased basal melting associated with an inflow of warm and salty water from the deep ocean onto the shelf via submarine glacial troughs. Modelling work suggests that variability in the transport of this source of heat across the shelf-break and onto the Dotson Trough in the western Amundsen Sea is regulated by wind-driven changes in an eastward undercurrent that flows along the continental slope. What controls the strength and variability of the undercurrent, however, is not well documented due to a lack of observations in the region. Here, we use mooring records of undercurrent velocity near the shelf break in the Amundsen Sea throughs in conjunction with a novel 5-year altimetric sea level product that includes measurements in regions of near-perennial ice cover to describe the connection between undercurrent variability and climate on seasonal to interannual time scales. We find a robust signature of the undercurrent variability that is linked to both a circumpolar coastal sea level signal as well as to the sea level in a region offshore in the Amundsen Sea. We discuss the implications of the undercurrent-sea level covariability in the context of local and remote atmospheric forcing. Our study provides a nexus between intra-seasonal barotropic dynamics and timescales when the baroclinicity of the flow becomes dominant.
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