Mid-Holocene intensification of Southern Hemisphere westerly winds and implications for regional climate dynamics

作者：Jamie Tamhane, Zoë Thomas, Haidee Cadd, Matthew R. P. Harris, Chris Turney, Christopher E. Marjo, Huixin Wang, Rabeya Akter, Panayiotis Panaretos, Amalia Yunita Halim, Patricia Gadd, Stefanie Carter, Paul Brickle · 发表于：Quaternary Science Reviews · 年份：2023 · DOI：10.1016/j.quascirev.2023.108007 · 被引用次数：10 · 研究领域：Geology and Paleoclimatology Research、Aeolian processes and effects、Climate variability and models

The Southern Hemisphere westerly winds (SWW), a belt of strong zonal winds in the mid-latitudes, play a key role in Southern Hemisphere climate variability. Recent intensification and southwards migration of the SWW is projected to continue due to anthropogenic climate change and despite a recovering Antarctic ozone hole, impacting regional hydroclimate, ocean circulation and carbon cycling. Despite the importance of the SWW, our understanding of their behaviour on centennial to millennial timescales is limited by the inherently short observational record and limited palaeo-archive agreement on the wind belt's Holocene dynamics. Here we utilise dust flux, Itrax core scanning, rare earth element composition and HYSPLIT particle modelling to present a 8700-year (10,500–1700 cal yr BP) reconstruction of local SWW intensity from a Falkland Islands (Islas Malvinas) peat sediment core which, along with other reconstructions, we interpret in a regional South Atlantic and hemispheric context. We find increased dust deposition and variability from ca. 5700 cal yr BP, signalling an intensification and possible southwards shift of the SWW, though Patagonia likely remains the primary distal dust source throughout our record. Additionally, we identify asymmetric behaviour in the SWW belt from 3000 to 1700 cal yr BP over southern South America and the southwest Atlantic. In alignment with these findings, we propose a possible eastwards projection of the Amundsen Sea Low (ASL) into the Sout...