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Bipolar seesaw in the northeastern tropical Atlantic during Heinrich stadials
Author(s) -
Zarriess Michelle,
Johnstone Heather,
Prange Matthias,
Steph Silke,
Groeneveld Jeroen,
Mulitza Stefan,
Mackensen Andreas
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl046070
Subject(s) - stadial , intertropical convergence zone , seesaw molecular geometry , geology , climatology , hadley cell , southern hemisphere , tropical atlantic , oceanography , climate change , sea surface temperature , geography , general circulation model , precipitation , holocene , physics , meteorology , nuclear physics , neutrino
Two SST records based on Mg/Ca of G. ruber (pink) from the continental slope off West Africa at 15°N and 12°N shed new light on the thermal bipolar seesaw pattern in the northeastern tropical Atlantic during periods of reduced Atlantic Meridional Overturning Circulation (AMOC) associated with Heinrich stadials H1 to H6. The two records indicate that the latitudinal position of the bipolar seesaw's zero‐anomaly line, between cooling in the North and warming in the South, gradually shifted southward from H6 to H1. A conceptual model is presented that aims to provide a physically consistent mechanism for the southward migration of the seesaw's fulcrum. The conceptual model suggests latitudinal movements of the Intertropical Convergence Zone, driven by a combination of orbital‐forced changes in the meridional temperature gradient within the realm of the Hadley cell and the expansion of the Northern Hemisphere cryosphere, as a major factor.