DOI: 10.1016/j.epsl.2018.02.044
Scopus记录号: 2-s2.0-85043449329
论文题名: Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model
作者: Thran A.C. ; Dutkiewicz A. ; Spence P. ; Müller R.D.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 489 起始页码: 228
结束页码: 240
语种: 英语
英文关键词: bottom current
; contourite
; eddy
; meridional overturning circulation
; ocean modelling
; sediment drift
Scopus关键词: Geographical distribution
; Kinetic energy
; Kinetics
; Oceanography
; Sediments
; Bottom current
; Contourite
; eddy
; Meridional overturning circulations
; Ocean modelling
; Sediment drift
; Ocean currents
; bottom current
; contourite
; drift behavior
; eddy
; meridional circulation
; numerical model
; overturn
; sediment transport
; sedimentation
; spatial distribution
; upper ocean
英文摘要: Contourite drifts are anomalously high sediment accumulations that form due to reworking by bottom currents. Due to the lack of a comprehensive contourite database, the link between vigorous bottom water activity and drift occurrence has yet to be demonstrated on a global scale. Using an eddy-resolving ocean model and a new georeferenced database of 267 contourites, we show that the global distribution of modern contourite drifts strongly depends on the configuration of the world's most powerful bottom currents, many of which are associated with global meridional overturning circulation. Bathymetric obstacles frequently modify flow direction and intensity, imposing additional finer-scale control on drift occurrence. Mean bottom current speed over contourite-covered areas is only slightly higher (2.2 cm/s) than the rest of the global ocean (1.1 cm/s), falling below proposed thresholds deemed necessary to re-suspend and redistribute sediments (10–15 cm/s). However, currents fluctuate more frequently and intensely over areas with drifts, highlighting the role of intermittent, high-energy bottom current events in sediment erosion, transport, and subsequent drift accumulation. We identify eddies as a major driver of these bottom current fluctuations, and we find that simulated bottom eddy kinetic energy is over three times higher in contourite-covered areas in comparison to the rest o.f the ocean. Our work supports previous hypotheses which suggest that contourite deposition predominantly occurs due to repeated acute events as opposed to continuous reworking under average-intensity background flow conditions. This suggests that the contourite record should be interpreted in terms of a bottom current's susceptibility to experiencing periodic, high-speed current events. Our results also highlight the potential role of upper ocean dynamics in contourite sedimentation through its direct influence on deep eddy circulation. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109965
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: EarthByte Group, School of Geosciences, University of Sydney, Sydney NSW, 2006, Australia; Climate Change Research Centre, University of New South Wales, Sydney NSW, 2052, Australia; ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney NSW, 2052, Australia; Sydney Informatics Hub, University of Sydney, Sydney NSW, 2006, Australia
Recommended Citation:
Thran A.C.,Dutkiewicz A.,Spence P.,et al. Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model[J]. Earth and Planetary Science Letters,2018-01-01,489