TY - JOUR

T1 - Global reorganization of atmospheric circulation during Dansgaard-Oeschger cycles

AU - Fohlmeister, Jens

AU - Sekhon, Natasha

AU - Columbu, Andrea

AU - Vettoretti, Guido

AU - Weitzel, Nils

AU - Rehfeld, Kira

AU - Veiga-Pires, Cristina

AU - Ben-Yami, Maya

AU - Marwan, Norbert

AU - Boers, Niklas

N1 - Publisher Copyright: © 2023 the Author(s).

PY - 2023/6/26

Y1 - 2023/6/26

N2 - Ice core records from Greenland provide evidence for multiple abrupt cold-warm- cold events recurring at millennial time scales during the last glacial interval. Although climate variations resembling Dansgaard-Oeschger (DO) oscillations have been identified in climate archives across the globe, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete. Here, we investigate the influence of DO-cold- to- warm transitions on the global atmospheric circulation pattern. We comprehensively analyze δ18O changes during DO transitions in a globally distributed dataset of speleothems and set those in context with simulations of a comprehensive high-resolution climate model featuring internal millennial-scale variations of similar magnitude. Across the globe, speleothem δ18O signals and model results indicate consistent large-scale changes in precipitation amount, moisture source, or seasonality of precipitation associated with the DO transitions, in agreement with northward shifts of the Hadley circulation. Furthermore, we identify a decreasing trend in the amplitude of DO transitions with increasing distances from the North Atlantic region. This provides quantitative observational evidence for previous suggestions of the North Atlantic region being the focal point for these archetypes of past abrupt climate changes.

AB - Ice core records from Greenland provide evidence for multiple abrupt cold-warm- cold events recurring at millennial time scales during the last glacial interval. Although climate variations resembling Dansgaard-Oeschger (DO) oscillations have been identified in climate archives across the globe, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete. Here, we investigate the influence of DO-cold- to- warm transitions on the global atmospheric circulation pattern. We comprehensively analyze δ18O changes during DO transitions in a globally distributed dataset of speleothems and set those in context with simulations of a comprehensive high-resolution climate model featuring internal millennial-scale variations of similar magnitude. Across the globe, speleothem δ18O signals and model results indicate consistent large-scale changes in precipitation amount, moisture source, or seasonality of precipitation associated with the DO transitions, in agreement with northward shifts of the Hadley circulation. Furthermore, we identify a decreasing trend in the amplitude of DO transitions with increasing distances from the North Atlantic region. This provides quantitative observational evidence for previous suggestions of the North Atlantic region being the focal point for these archetypes of past abrupt climate changes.

KW - climate model

KW - glacial climate

KW - speleothem

KW - stadial-interstadial transitions

U2 - 10.1073/pnas.2302283120

DO - 10.1073/pnas.2302283120

M3 - Journal article

C2 - 37639590

AN - SCOPUS:85168930240

VL - 120

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 36

M1 - e2302283120

ER -