Deepwater formation in the Southern Weddell Sea, processes, pathways and fluxes

Ice Shelf Water (ISW) is the final product of the melting process underneath the floating ice shelves in the Antarctica. Recent drastic break-ups of the Larsen ice-shelf in the Weddell Sea has vitalised the question if this melting has increased. The most efficient production of ISW takes place under the immense Ronne - Filchner Ice shelves in the Southern Weddell Sea. The corresponding ISW flow out of the region was located in 1977, and a key location for long term monitoring was identified. Since then we have succeeded in occupying this station with instrumented moorings for about 5 years, which have given us valuable information of variability of the sub-ice shelf and continental shelf circulation. However, in addition to serve as an indicator for Antarctic ice-cap melting, it turns out that the ISW flow contribute to the formation of the Antarctic bottom water. Therefore it is driving the thermohaline circulation, which has a great impact on the global climate. There are several processes and regions in the Antarctic of importance for the bottom water formation. However, recent international efforts indicate that the ISW overflow and its cascading towards large oceans depths as a bottom trapped jet entrain waters from above, increasing the volume transport by a factor of about 2.5. The resulting volume transport estimates indicate that the processes involving ISW is dominating the deep and bottom water formation in the Antarctic.