| 14 Apr 2025
The effect of storms on the Antarctic Slope Current and the warm inflow onto the southeastern Weddell Sea continental shelf
Abstract. The southern Weddell Sea and the Filchner Ice Shelf cavity are locations of dense bottom water production and are thus connected to the global climate system. However, it has been suggested that increased heat transport from the deep ocean onto the continental shelf and towards the ice cavities would disrupt the dense water production and increase ice shelf melt rates. Processes that affect the southward heat transport are, therefore, important to understand. Sudden strong westward ocean surface stress events – "storms" – are suggested to drive enhanced southward transport of modified Warm Deep Water across the continental shelf in the Filchner Trough region in the southeastern Weddell Sea. We use a mooring network with up to four-year-long mooring records from the region to investigate how the ocean circulation responds to storm events. We find that about 70 % of the events that last longer than four days, have a cumulative westward stress increase larger than 0.4N m−2 day−1, and a maximum stress above 0.25N m−2 leads to a significant increase in the speed of the Antarctic Slope Current (ASC) just upstream of Filchner Trough. Roughly one-third of the identified storm events cause an increased southward current speed on the shelf. At the southernmost mooring, 76° S, storm responses are observed mainly during the latter part of the record (mid-2019 to early 2021). This interannual variability in storm response indicates a potential dependency on background hydrography and circulation that remains to be fully explained. This study highlights the potential importance of storms for southward heat transport towards the Antarctic ice shelves. Warm water that is present on the continental shelf during a storm will likely be pushed southward by the enhanced circulation, increasing the southward heat transport and the likelihood that it reaches the ice shelf front before the heat is lost to the atmosphere during winter.
