The Southern Westerlies During the Holocene: Paleoenvironmental Reconstructions from Chilean Lake, Fjord, and Ocean Margin Sediments Combined with Climate Modeling

Abstract

This project aimed at investigating centennial to millennial-scale changes of the strength and position of the southern westerly wind belt (SWW) using multi-proxy paleoprecipitation and paleoceanographic records combined with transient model runs. The proxy data records reveal a distinct latitudinal anti-phasing of wind changes between the core and northern margin of the SWW over the Holocene. During the early Holocene, the SWW core was enhanced and the northern margin was reduced, whereas the opposite pattern is observed in the late Holocene. These Holocene changes resemble modern seasonal wind belt variations and can be best explained by varying sea-surface temperature fields in the eastern South Pacific. Transient modeling experiments from the mid- to late Holocene are not yet consistent with these proxy results. However, a good data-model agreement exists when investigating the potential impact of solar variability on the SWW at centennial time-scales during the latest Holocene with periods of lower (higher) solar activity causing equatorward (southward) shifts of the SWW.