An early Holocene westerly minimum in the southern mid-latitudes

Moreno, P., I; Henriquez, W., I; Pesce, O. H.; Henriquez, C. A.; Fletcher, M. S.; Garreaud, R. D.; Villa-Martinez, R. P.


An important coupled ocean-atmospheric system in the mid- and high latitudes involves the Southern Westerly Winds (SWW) and the Southern Ocean (SO), which controls climate in the southernmost third of the world, deep water formation, and ventilation of CO2 from the deep ocean. Most studies have examined its role as a driver of atmospheric CO2 concentrations during glacial terminations, but very few have investigated its influence during the Holocene, i.e. the current interglacial. A fundamental problem, however, is resolving whether the SWW strength increased or declined during the early Holocene (similar to 11.5-7.5 ka, ka = 1000 cal yr BP) in sectors adjacent to the Drake Passage. Here we assess past changes in SWW influence over the last similar to 17,000 years using terrestrial paleoclimate records from southwestern Patagonia (similar to 52 degrees S). We detect a zonally symmetric Early Holocene Westerly Minimum which diminished wind stress and upwelling on the SO, contributing to a contemporary decline in atmospheric CO2 concentrations and enrichment in the stable carbon isotope ratio of atmospheric CO2 (delta C-13(atm)). Our midlatitude data also indicate a shift to strong SWW influence at similar to 7.5 ka which correlates with a sustained increase in atmospheric CO2 and halt in the delta C-13(atm) rise, suggesting enhancement of high-latitude ocean ventilation by an invigorated SWW-SO coupled system. (C) 2020 Elsevier Ltd. All rights reserved.

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Título según WOS: An early Holocene westerly minimum in the southern mid-latitudes
Volumen: 251
Fecha de publicación: 2021


Notas: ISI