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Extratropical forcing of Sahel aridity during Heinrich stadials
Author(s) -
Niedermeyer E. M.,
Prange Matthias,
Mulitza Stefan,
Mollenhauer Gesine,
Schefuß Enno,
Schulz Michael
Publication year - 2009
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 - 10.1029/2009gl039687
Subject(s) - stadial , alkenone , extratropical cyclone , climatology , geology , sea surface temperature , oceanography , atlantic multidecadal oscillation , tropical atlantic , forcing (mathematics) , arid , holocene , paleontology
In order to investigate a possible link between tropical Northeast (NE) Atlantic sea‐surface temperature (SST), Atlantic meridional overturning circulation (AMOC), and drought in the Sahel during the past 44 thousand years (kyr) we used alkenone paleothermometry and δ 13 C of C. wuellerstorfi of a marine sediment core from the continental slope off Senegal. Our data show periods of low SST and reduced AMOC that coincided with drought in the Sahel during North Atlantic Heinrich stadials (HS). The coldest period was HS1 (ca. 15–18 kyr before present, BP) when SST decreased by more than 2°C. Moreover, the SST off Senegal lagged variations in Sahel aridity, which is in agreement with results from a freshwater hosing experiment. We conclude that variations in tropical NE Atlantic SST were not the initial trigger of millennial‐scale Sahel droughts of the past 44 kyr. Instead, it is thought that these droughts were induced by substantial coolings of the extratropical North Atlantic.