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

• Published in: Quaternary Science Reviews
• Main Authors: Pedro, J.B., Andersson, Carin, Vettoretti, G., Voelker, A.H.L., Waelbroeck, C., Dokken, Trond Martin, Jensen, Mari Fjalstad, Rasmussen, S.O., Sessford, Evangeline, Jochum, M., Nisancioglu, Kerim Hestnes
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Greenland; Nordic Seas; North Atlantic; Sea ice
• Online Access: https://hdl.handle.net/11250/3023873; https://doi.org/10.1016/j.quascirev.2022.107599

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. publishedVersion