Similarities and differences in circulation beneath the Filchner- Ronne and Ross Ice Shelves: A Lagrangian point of view

We compared circulations under the Filchner-Ronne Ice Shelf (FRIS) and the Ross Ice Shelf (RIS) using output from the Whole Antarctica Ocean Model driven by repeated year atmospheric forcing and processed by the particle-tracking Parcels model. Three Lagrangian characteristics were calculated: the visitation frequency, the mean age, and the representative particle trajectory. In both FRIS and RIS, the High Salinity Shelf Water (HSSW) entered through depressions off the western coast of ice shelves. We found that HSSW transformed into the Ice Shelf Water that departed both ice shelves at central ice front locations (approximately 58-57°W in Ronne Ice Shelf and 175°W in RIS). The outflow through the Ronne Ice Front we identified has not attracted attention until now, although it has been observed. Almost half of the particles departed FRIS through the Ronne Ice Front, whereas about 20% stayed under FRIS. The rest of the particles flow out through the Filchner Trough. In contrast, only 2% of the particles stayed under RIS. The mean age of water leaving FRIS through the Ronne Ice Front and the water leaving RIS was 7–8 years, whereas the water leaving FRIS through the Filchner Trough was about 10 years.