气候变化领域集成服务门户(CCPortal): Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years

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DOI	10.5194/cp-16-1127-2020
	Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years
	Lochte A.A.; Schneider R.; Kienast M.; Repschläger J.; Blanz T.; Garbe-Schönberg D.; Andersen N.
发表日期	2020
ISSN	18149324
起始页码	1127
结束页码	1143
卷号	16 期号:4
英文摘要	The Labrador Sea is important for the modern global thermohaline circulation system through the formation of intermediate Labrador SeaWater (LSW) that has been hypothesized to stabilize the modern mode of North Atlantic deep-water circulation. The rate of LSW formation is controlled by the amount of winter heat loss to the atmosphere, the expanse of freshwater in the convection region and the inflow of saline waters from the Atlantic. The Labrador Sea, today, receives freshwater through the East and West Greenland currents (EGC, WGC) and the Labrador Current (LC). Several studies have suggested the WGC to be the main supplier of freshwater to the Labrador Sea, but the role of the southward flowing LC in Labrador Sea convection is still debated. At the same time, many paleoceanographic reconstructions from the Labrador Shelf focussed on late deglacial to early Holocene meltwater run-off from the Laurentide Ice Sheet (LIS), whereas little information exists about LC variability since the final melting of the LIS about 7000 years ago. In order to enable better assessment of the role of the LC in deep-water formation and its importance for Holocene climate variability in Atlantic Canada, this study presents high-resolution middle to late Holocene records of sea surface and bottom water temperatures, freshening, and sea ice cover on the Labrador Shelf during the last 6000 years. Our records reveal that the LC underwent three major oceanographic phases from the mid- to late Holocene. From 6.2 to 5.6 ka, the LC experienced a cold episode that was followed by warmer conditions between 5.6 and 2.1 ka, possibly associated with the late Holocene thermal maximum. While surface waters on the Labrador Shelf cooled gradually after 3 ka in response to the neoglaciation, Labrador Shelf subsurface or bottom waters show a shift to warmer temperatures after 2.1 ka. Although such an inverse stratification by cooling of surface and warming of subsurface waters on the Labrador Shelf would suggest a diminished convection during the last 2 millennia compared to the mid-Holocene, it remains difficult to assess whether hydrographic conditions in the LC have had a significant impact on Labrador Sea deep-water formation. © 2020 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	climate variation; deep water formation; deglaciation; estuarine front; Holocene; Hypsithermal; ice cover; Laurentide Ice Sheet; paleoceanography; sea ice; stratification; thermohaline circulation; water mass; Atlantic Coast [Canada]; Atlantic Coast [North America]; Atlantic Ocean; Atlantic Ocean (North); Canada; Labrador Current; Labrador Sea; Labrador Shelf
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146701
作者单位	Institute of Geoscience, Kiel University, Ludewig-Meyn Str. 10, Kiel, 24118, Germany; HOSST Graduate School, GEOMAR Helmholtz-Centre for Ocean Research Kiel, Wischofstraße 1-3, Kiel, 24148, Germany; Department of Oceanography, Dalhousie University, 1355 Oxford Street, Halifax, Canada; Department of Climate Geochemistry, Max Planck Institute for Chemistry, Hahn Meitner Weg 1, Mainz, 55128, Germany; Leibniz Laboratory for Radiometric Dating and Stable Isotope Research, Kiel University, Max-Eyth-Str. 11-13, Kiel, 24118, Germany
推荐引用方式 GB/T 7714	Lochte A.A.,Schneider R.,Kienast M.,et al. Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years[J],2020,16(4).
APA	Lochte A.A..,Schneider R..,Kienast M..,Repschläger J..,Blanz T..,...&Andersen N..(2020).Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years.Climate of the Past,16(4).
MLA	Lochte A.A.,et al."Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years".Climate of the Past 16.4(2020).