Dansgaard-Oeschger and Heinrich event temperature anomalies in the North Atlantic set by sea ice, frontal position and thermocline structure

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We use eighteen timescale-synchronised near-surface temperature reconstructions spanning 10–50 thousand years before present to clarify the regional expression of Dansgaard-Oeschger (D-O) and Heinrich (H) events in the North Atlantic. The North Atlantic Drift region shows D-O temperature variations of ca. 2–5° with Greenland-like structure. The Western Iberian Margin region also shows Greenland-like structure, but with more pronounced surface cooling between interstadials and Heinrich stadials (ca. 6–9 °C) than between interstadials and non-Heinrich stadials (ca. 2–3 °C). The southern Nordic Seas show smaller D-O temperature anomalies (ca. 1–2 °C) that appear out of phase with Greenland. These spatial patterns are replicated in a new global climate model simulation that features unforced (D-O-like) and freshwater forced (H-like) abrupt climate changes. The model simulations and observations suggest consistently that the spatial expression and amplitude of D-O and H event temperature anomalies are dominated by coupled changes in the Atlantic Meridional Overturning, sea ice extent, polar front position and thermocline structure.

TidsskriftQuaternary Science Reviews
Antal sider16
StatusUdgivet - 1 aug. 2022

Bibliografisk note

Funding Information:
This research was supported by the European Research Council under the European Community's Seventh Framework Programme ( FP7/2007–2013 )/ ERC grant agreement 610055 (the ice2ice project) and by the ChronoClimate project funded by the Carlsberg Foundation . A.V. acknowledges funding support from FCT - Foundation for Science and Technology through projects UIDB/04326/2020 and IF/01500/2014 . J.B.P acknowledges support from the Australian Government Department of Industry Science Energy and Resources , grant ASCI000002 . C.W. acknowledges support from the European Research Council grant ACCLIMATE/339108 . S.O.R. acknowledges support from the IceFlow project funded by the VILLUM Foundation . The authors thank ice2ice project colleagues and the many palaeoceanographers who made their data available. We are grateful to the anonymous reviewers for constructive comments that improved the manuscript.

Publisher Copyright:
© 2022 The Authors

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