气候变化领域集成服务门户(CCPortal): Distinguishing current effects in sediments delivered to the ocean by ice. II. Glacial to Holocene changes in high latitude North Atlantic upper ocean flows

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DOI	10.1016/j.quascirev.2019.105902
	Distinguishing current effects in sediments delivered to the ocean by ice. II. Glacial to Holocene changes in high latitude North Atlantic upper ocean flows
	McCave I.N.; Andrews J.T.
发表日期	2019
ISSN	0277-3791
卷号	223
英文摘要	Shallow ocean flows in the northern North Atlantic are of key importance in the regulation of Earth's climate. In the northern North Atlantic nutrient-rich cold Arctic Ocean outflow (of modified Atlantic water) plus Pacific and ice-melt waters flow in the East Greenland Current (EGC) and in the Baffin Island Current which feeds into the Labrador Current. The outflows east of Greenland carry a substantial amount of warm salty North Atlantic water that flows into the Nordic Seas, mixes, recirculates – much of it via the Arctic Ocean - and contributes to both shallow and deep overflows. A key to understanding oceanic control of Earth's climate therefore resides in establishing the changes in these high-latitude currents. We have analysed 28 cores comprising ∼2900 measured samples in the high-latitude N. Atlantic and Arctic Oceans of which >80% pass the reliability test of a correlation coefficient between sortable silt mean and percentage r > 0.5 (McCave and Andrews, 2019, Quat. Sci. Rev. 212, 92–107). There is a close similarity between the pattern of Holocene decrease in the strength of the Irminger Current inflow to the Nordic Seas and outflow recorded in the EGC and in deep overflow east of Reykjanes Ridge. This suggests that the flow of the EGC is strongly influenced by the influx of North Atlantic water, rather than supply of fresher water from ice sheet melt or Pacific origin. In contrast to the flows east of Greenland, those west of Greenland show a slow Holocene increase in flow. The freshest/coldest deep Denmark Strait overflow recorded at Orphan Knoll, as well as Labrador Sea water flow on the slope north of the Grand Banks, also show this gradual increase. This points to control on deep water overflows by the flux of cold fresh water from Greenland and the Arctic, some of which may have come from the Pacific via the Bering Strait. Models also show a Holocene east-west difference in deep-water formation with increase in the Labrador Sea and decrease in the Nordic seas. In almost all cases Holocene flow speed maxima lag the local Holocene Thermal Maxima by between 0 and 1000 years. It is therefore highly unlikely that the local Holocene thermal maxima are responses to increased flow of shallow currents in the adjacent ocean areas. Decelerations in flow speed accompany Holocene coolings, while accelerations accompany warmings. The LGM was a period of slow flow, and meltwater events usually show slowdowns as well. However, Heinrich events show slowdowns in some regions and faster flow in others. © 2019 Elsevier Ltd
语种	英语
scopus关键词	Earth (planet); Flow of water; Ice; Mooring; Seawater; Correlation coefficient; Deep-water formation; Denmark Strait overflows; East greenland currents; Irminger currents; Labrador Current; Labrador sea waters; North Atlantic waters; Ocean currents; cooling; deep water; Holocene; ice sheet; Last Glacial Maximum; latitude; meltwater; sediment transport; upper ocean; water flow; Arctic; Arctic Ocean; Atlantic Ocean; Atlantic Ocean (North); Baffin Island; Bering Strait; Canada; Denmark Strait; East Greenland Current; Grand Banks; Irminger Current; Labrador Current; Labrador Sea; Norwegian Sea; Nunavut; Reykjanes Ridge
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/151745
作者单位	Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom; Department of Geological Sciences and INSTAAR, University of Colorado, Boulder, CO 80309, United States
推荐引用方式 GB/T 7714	McCave I.N.,Andrews J.T.. Distinguishing current effects in sediments delivered to the ocean by ice. II. Glacial to Holocene changes in high latitude North Atlantic upper ocean flows[J],2019,223.
APA	McCave I.N.,&Andrews J.T..(2019).Distinguishing current effects in sediments delivered to the ocean by ice. II. Glacial to Holocene changes in high latitude North Atlantic upper ocean flows.Quaternary Science Reviews,223.
MLA	McCave I.N.,et al."Distinguishing current effects in sediments delivered to the ocean by ice. II. Glacial to Holocene changes in high latitude North Atlantic upper ocean flows".Quaternary Science Reviews 223(2019).