Abstract
The average rate of melting at the base of the large Filchner-Ronne Ice Shelf in the southern Weddell Sea is currently low, but projected to increase dramatically within the next century. In a model study, melt rates increase as changing ice conditions cause a redirection of a coastal current, bringing warm water of open ocean origin through the Filchner Depression and into the Filchner Ice Shelf cavity. Here we present observations from near Filchner Ice Shelf and from the Filchner Depression, which show that pulses of warm water already arrive as far south as the ice front. This southward heat transport follows the eastern flank of the Filchner Depression and is found to be directly linked to the strength of a wind-driven coastal current. Our observations emphasize the potential sensitivity of Filchner-Ronne Ice Shelf melt rates to changes in wind forcing.
Highlights
The average rate of melting at the base of the large Filchner-Ronne Ice Shelf in the southern Weddell Sea is currently low, but projected to increase dramatically within the century
In the southern Weddell Sea, where the large Filchner-Ronne Ice Shelf (FRIS) resides (Fig. 1), the water on the wide continental shelf separating the ice-shelf cavity from the deep ocean is cold, and the majority of the water entering the ice-shelf cavity is at the surface freezing point[6]
FD is a deep trough that cuts across the eastern part of the broad continental shelf in the southern Weddell Sea, and extends beneath Filchner Ice Shelf (FIS) to the south (Fig. 1)
Summary
The average rate of melting at the base of the large Filchner-Ronne Ice Shelf in the southern Weddell Sea is currently low, but projected to increase dramatically within the century. Basal melt rates in this region are currently low[7], recent modelling studies[8,9] suggest that changing ice conditions during the century will affect the transfer of momentum from the atmosphere to the ocean and redirect the coastal current in a way that will allow the Warm Deep Water (WDW) to access the Filchner Ice Shelf (FIS) cavity through the Filchner Depression (FD, Fig. 1).
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