气候变化领域集成服务门户(CCPortal): Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record

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DOI	10.1016/j.quascirev.2020.106169
	Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record
	Li C.; Sonke J.E.; Le Roux G.; Van der Putten N.; Piotrowska N.; Jeandel C.; Mattielli N.; Benoit M.; Wiggs G.F.S.; De Vleeschouwer F.
发表日期	2020
ISSN	0277-3791
卷号	231
英文摘要	The southern westerly winds (SWW) play a major role in climate variability in Southern Hemisphere mid- and high-latitudes, regulating rainfall, ocean circulation, and the Southern Ocean carbon sink. Despite their importance, little is known about millennial scale changes in the SWW and how they have influenced the climate system in the past and interacted with the Earth's surface elements, such as dust, nutrients and carbon. Here we present a dust record from a 6.6 kyr old peat core in Amsterdam Island (AMS) situated at the northern edge of the SWW (37°S) in the Southern Indian Ocean. Mineral dust flux was used to track atmospheric dust production, long-distance transport and subsequent deposition. Dust provenance was determined from rare earth element (REE) and Nd isotopic signatures (εNd) in the peat core, compared with a reference dataset of Southern Hemisphere dust sources. Using a multi-proxy mixing model, the εNd and REE ratios show a relatively uniform mixture of ca. 40% local, 15% Southern African and 45% Southern South American dust sources since 6.6 cal kyr BP. However, from 1910 AD onwards, there is a doubling in the contribution from Southern Africa (32%). Two mineral dust flux minima occur at 6.2–4.9 cal kyr BP and 3.9–2.7 cal kyr BP, interpreted as periods with equatorward-shifted and/or strengthened SWW at the northern edge of the wind belt. Conversely, periods of higher dust flux at 6.6–6.2 cal kyr BP, 4.9–3.9 cal kyr BP, and 1.4 cal kyr BP onwards are interpreted as poleward-shifted and/or weakened SWW. These interpretations are based on the findings that higher (lower) wind speeds lead to enhanced (less) removal of distal dust on the way to AMS, by wet deposition and turbulence. Published Holocene SWW records at the northern edge of the wind belt (33–41°S) covering South-America, Southern-Africa and Australia, show much variability over the last 6.6 kyr. We suggest this reflects complex regional climate variability in the different SH longitudinal sectors, indicating that SWW are not zonally homogeneous at the northern edge of the wind belt. The recent shift in dust provenance is not accompanied by enhanced total dust deposition at AMS. We therefore suggest that human impact (e.g., land use changes) and drier climate conditions in Southern Africa have led to enhanced dust mobilization. © 2020 Elsevier Ltd
英文关键词	Amsterdam Island; Anthropogenic activities; Dust sources; Peat; Southern westerly winds
语种	英语
scopus关键词	Belts; Carbon; Climate change; Deposition; Earth (planet); Land use; Landforms; Oceanography; Peat; Rare earths; Wind; Amsterdam; Anthropogenic activity; Dust sources; Isotopic signatures; Long-distance transport; Southern Hemisphere; Southern indian ocean; Southern westerly winds; Dust; anthropogenic effect; climate conditions; dust; Holocene; human activity; land use; mineral dust; peat; provenance; rare earth element; regional climate; Southern Hemisphere; westerly; wet deposition; Africa; Amsterdam Island; French Southern Territories; Indian Ocean; Southern Africa; Southern Ocean
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151581
作者单位	EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France; Laboratoire Géosciences Environnement Toulouse, Université de Toulouse, CNRS, IRD, UPS, Toulouse, France; Faculty of Science, Earth Sciences, Cluster Earth and Climate, Vrije Universiteit Amsterdam, Netherlands; Silesian University of Technology, Institute of Physics-CSE, Gliwice, Poland; LEGOS Université de Toulouse, CNRS, CNES, IRD, UPS, Toulouse, France; Laboratoire G-Time, DGES, Université Libre de Bruxelles (ULB), Belgium; School of Geography and the Environment, Oxford University Centre for the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, United Kingdom
推荐引用方式 GB/T 7714	Li C.,Sonke J.E.,Le Roux G.,et al. Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record[J],2020,231.
APA	Li C..,Sonke J.E..,Le Roux G..,Van der Putten N..,Piotrowska N..,...&De Vleeschouwer F..(2020).Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record.Quaternary Science Reviews,231.
MLA	Li C.,et al."Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record".Quaternary Science Reviews 231(2020).