Observations of the shelf break current in the southern Weddell Sea: seasonal variability and mean state

• Main Authors: Darelius, Elin, Fer, Ilker, Janout, Markus Andre, Daae, Kjersti, Steiger, Nadine
• Format: Other/Unknown Material
• Language: unknown
• Published: Authorea, Inc. 2023
• Subjects: Antarctic; Filchner Trough; Ronne Ice Shelf; The Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Shelf
• Online Access: http://dx.doi.org/10.22541/essoar.169945617.72057337/v1

The Antarctic Slope Front and the associated Antarctic Slope Current are central in determining the dynamics along and the exchanges across the continental shelf break around Antarctica. Here, we present new, four-year-long (2017-2021) records from two moorings deployed on the upper part of the continental slope (530 m and 738 m depth) just upstream of the Filchner Trough in the southern Weddell Sea. We use the records to describe the mean state and the seasonal variability of the shelf break current and the regional hydrography. We find that (i) the current is bottom enhanced, (ii) the isotherms slope upwards towards the shelfbreak, and more so for warmer isotherms, and (iii) the monthly mean thermocline depth is shallowest in February-March and deepest in May-June while (iv) the current is strongest in April-June. On monthly timescales, we show that (v) positive (warm) temperature anomalies of the de-seasoned records are associated with weaker-than-usual currents. Our results contribute to the understanding of how warm ocean waters propagate southward and potentially affect basal melt rates at the Filchner-Ronne Ice Shelf.