DOI: 10.1038/ngeo2037
论文题名: Minimal change in antarctic circumpolar current flow speed between the last glacial and holocene
作者: McCave I.N. ; Crowhurst S.J. ; Kuhn G. ; Hillenbrand C.-D. ; Meredith M.P.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 2 起始页码: 113
结束页码: 116
语种: 英语
Scopus关键词: buoyancy
; carbon dioxide
; circumpolar current
; current direction
; grain size
; Holocene
; Last Glacial
; overturn
; paleoceanography
; reconstruction
; sediment core
; temporal variation
; westerly
; Antarctic Circumpolar Current
; Southern Ocean
英文摘要: The Antarctic Circumpolar Current is key to the mixing and ventilation of the world's oceans. This current flows from west to east between about 45and 70S (refs,) connecting the Atlantic, Pacific and Indian oceans, and is driven by westerly winds and buoyancy forcing. High levels of productivity in the current regulate atmospheric CO 2 concentrations. Reconstructions of the current during the last glacial period suggest that flow speeds were faster or similar to present, and it is uncertain whether the strength and position of the westerly winds changed. Here we reconstruct Antarctic Circumpolar Current bottom speeds through the constricting Drake Passage and Scotia Sea during the Last Glacial Maximum and Holocene based on the mean grain size of sortable silt from a suite of sediment cores. We find essentially no change in bottom flow speeds through the region, and, given that the momentum imparted by winds, and modulated by sea-ice cover, is balanced by the interaction of these flows with the seabed, this argues against substantial changes in wind stress. However, glacial flow speeds in the sea-ice zone south of 56S were significantly slower than present, whereas flow in the north was faster, but not significantly so. We suggest that slower flow over the rough topography south of 56S may have reduced diapycnal mixing in this region during the last glacial period, possibly reducing the diapycnal contribution to the Southern Ocean overturning circulation. © 2014 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106464
Appears in Collections: 气候减缓与适应 科学计划与规划
There are no files associated with this item.
作者单位: Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom; Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Am Alten Hafen 26, Bremerhaven D-27568, Germany; British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom; Scottish Association for Marine Science, Oban PA37 1QA, United Kingdom
Recommended Citation:
McCave I.N.,Crowhurst S.J.,Kuhn G.,et al. Minimal change in antarctic circumpolar current flow speed between the last glacial and holocene[J]. Nature Geoscience,2014-01-01,7(2)