Interglacial Antarctic–Southern Ocean climate decoupling due to moisture source area shifts

Wilkes subglacial basin ice sheet response to Southern Ocean warming during late Pleistocene interglacials

“…This second-order parameter is an indicator of climate conditions in the vapour source regions, and is therefore sensitive to changes in the provenance areas or changes in air mass trajectories towards the sites 38 – 40 . Our comparison shows no clear differences between the TALDICE and EDC 41 d -excess profiles, which exhibit consistent patterns during interglacial stages (Fig. 2b ), as already observed for shorter warming events 42 .…”

“…2b ), as already observed for shorter warming events 42 . In particular, the increases in d -excess for TALDICE and EDC during MIS 5.5, MIS 7.5, and MIS 9.3 occur over longer time intervals than the δ 18 O increase, and the maxima in d -excess are reached in the second half of the interglacial period 41 but before the second δ 18 O anomaly in the TALDICE record. In summary, the absence of peculiarities in the d -excess records during the intervals with δ 18 O anomalies at TALDICE suggests that there are no significant variations of moisture sources 40 , 43 that could explain the TALDICE isotopic behaviour.…”

“…TALDICE ssNa + fluxes for Marine Isotopic Stage (MIS) 7.5 and 9.3 are from this study. b EDC 41 and TALDICE 28 d-excess records. TALDICE d-excess records for MIS 5.5, 7.5, and 9.3 are from this study.…”

“…TALDICE d-excess records for MIS 5.5, 7.5, and 9.3 are from this study. c EDC 36 , 37 , 41 and TALDICE 30 , 34 δ 18 O records. TALDICE δ 18 O data for MIS 7.5 and 9.3 are from this study.…”

“…During interglacial periods, the combination of increasing insolation and decreasing ice sheet volume leads to the steepening of the meridional temperature gradient, which strengthens and shifts the Southern Westerly Winds poleward, promoting upwelling in the Southern Ocean 42 , 57 . In addition, the deglacial weakening of the Atlantic Meridional Overturning Circulation may have led to warmer Southern Ocean temperatures through the bipolar seesaw mechanism, with early interglacial atmospheric warming also attributable to CO 2 escape from deep waters 41 , 58 , 59 . The more southerly and warmer Antarctic Circumpolar Current could have induced a dynamic response in the EAIS during MIS 5.5 60 , 61 and a comparable scenario can also be anticipated for MIS 9.3.…”