Fig. 4
From: Spatio-temporal variability of processes across Antarctic ice-bed–ocean interfaces
Schematics of bathymetric control on open-ocean circulation. Impact of long-term continental shelf expansion on the Southern Ocean high-latitude circulation in the Weddell Sea during the mid-Miocene a, during the late-Pleistocene b, and under modern-like climate conditions. During mid-Miocene (a), high-latitude ocean circulation is shifted southward due to the smaller continental shelf break63 compared with the modern one (b). Westerly winds are almost aligned with ACC, which strengthens the Gyre circulation and amplifies the inflow of CDW and outflow of AABW89 across the shelf break, also favored by stronger Easterly winds. At glacial/interglacial timescale, the incursions of CDW on the continental shelf are controlled by the depth and morphology of the continental slope and break97,117. During glacial periods c, with low atmospheric CO2 (< 200 p.p.m.), the AIS expands and the Westerly winds shift northward. Ice-sheet advance on the continental shelf inhibits oceanic circulation, which limits the incursions of CDW118. During ice-sheet retreat from the continental shelf edge, shallow-shelf ocean circulation is restored. Model simulations of super interglacials suggest that Westerly and Easterly winds are strengthened and are shifted polewards compared to their modern position d. This enhances incursions of CDW on the continental shelf, increasing the heat supply to the AIS grounding line, and promoting the formation and export of relatively fresh AABW94. However, depending on the depth of the continental shelf break and the strength of the Easterly winds modulated by atmospheric teleconnections, CDW may or may not intrude on the continental shelf, despite warm conditions
