Abstract : 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.
https://hal-insu.archives-ouvertes.fr/insu-03746437 Contributor : Nathalie POTHIERConnect in order to contact the contributor Submitted on : Friday, August 5, 2022 - 2:19:43 PM Last modification on : Tuesday, August 9, 2022 - 3:28:45 AM
J. B. Pedro, C. Andersson, G. Vettoretti, A. H. L. Voelker, C. Waelbroeck, et al.. Dansgaard-Oeschger and Heinrich event temperature anomalies in the North Atlantic set by sea ice, frontal position and thermocline structure. Quaternary Science Reviews, Elsevier, 2022, 289, ⟨10.1016/j.quascirev.2022.107599⟩. ⟨insu-03746437⟩