title: 155,000 years of West African monsoon and ocean thermal evolution.
abstract: A detailed reconstruction of West African monsoon hydrology over the past 155,000 years suggests a close linkage to northern high-latitude climate oscillations. Ba/Ca ratio and oxygen isotope composition of planktonic foraminifera in a marine sediment core from the Gulf of Guinea, in the eastern equatorial Atlantic (EEA), reveal centennial-scale variations of riverine freshwater input that are synchronous with northern high-latitude stadials and interstadials of the penultimate interglacial and the last deglaciation. EEA Mg/Ca-based sea surface temperatures (SSTs) were decoupled from northern high-latitude millennial-scale fluctuation and primarily responded to changes in atmospheric greenhouse gases and low-latitude solar insolation. The onset of enhanced monsoon precipitation lags behind the changes in EEA SSTs by up to 7000 years during glacial-interglacial transitions. This study demonstrates that the stadial-interstadial and deglacial climate instability of the northern high latitudes exerts dominant control on the West African monsoon dynamics through an atmospheric linkage.
authors.affiliation: Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA 93106-9630, USA. sweldeab@ifm-geomar.de
authors.forename: Syee
authors.initials: S
authors.lastname: Weldeab
authors.forename: David W
authors.initials: DW
authors.lastname: Lea
authors.forename: Ralph R
authors.initials: RR
authors.lastname: Schneider
authors.forename: Nils
authors.initials: N
authors.lastname: Andersen