DOI: 10.1002/grl.50684
论文题名: Turbulent mixing and hydraulic control of abyssal water in the Samoan Passage
作者: Alford M.H. ; Girton J.B. ; Voet G. ; Carter G.S. ; Mickett J.B. ; Klymak J.M.
刊名: Geophysical Research Letters
ISSN: 0094-8618
EISSN: 1944-8349
出版年: 2013
卷: 40, 期: 17 起始页码: 4668
结束页码: 4674
语种: 英语
英文关键词: abyss
; hydraulics
; mixing
Scopus关键词: abyss
; Abyssal circulation
; Horizontal resolution
; Hydraulic control
; Hydraulic response
; Shear instability
; Turbulence level
; Turbulent mixing
; Bathymetry
; Hydraulic machinery
; Hydraulics
; Mixing
; Turbulence
; Shear flow
; abyssal circulation
; bathymetry
; dense water
; hydraulics
; salinity
; seafloor
; shear
; sill
; turbulence
; turbulent mixing
; Pacific Ocean
; Pacific Ocean (South)
英文摘要: We report the first direct turbulence observations in the Samoan Passage (SP), a 40 km wide notch in the South Pacific bathymetry through which flows most of the water supplying the North Pacific abyssal circulation. The observed turbulence is 1000 to 10,000 times typical abyssal levels - strong enough to completely mix away the densest water entering the passage - confirming inferences from previous coarser temperature and salinity sections. Accompanying towed measurements of velocity and temperature with horizontal resolution of about 250 m indicate the dominant processes responsible for the turbulence. Specifically, the flow accelerates substantially at the primary sill within the passage, reaching speeds as great as 0.55 m s-1. A strong hydraulic response is seen, with layers first rising to clear the sill and then plunging hundreds of meters downward. Turbulence results from high shear at the interface above the densest fluid as it descends and from hydraulic jumps that form downstream of the sill. In addition to the primary sill, other locations along the multiple interconnected channels through the Samoan Passage also have an effect on the mixing of the dense water. In fact, quite different hydraulic responses and turbulence levels are observed at seafloor features separated laterally by a few kilometers, suggesting that abyssal mixing depends sensitively on bathymetric details on small scales. Key Points Observed turbulence is intense enough to affect properties of the flow Turbulence is due to shear instability and breaking lee waves Turbulence is strongly spatially variable ©2013. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883452897&doi=10.1002%2fgrl.50684&partnerID=40&md5=ab8feb49a1a037f65347cb01ccf038ff
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/5882
Appears in Collections: 气候减缓与适应
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作者单位: Applied Physics Laboratory, School of Oceanography, University of Washington, 1013 NE 40th St., Seattle, WA 98105, United States
Recommended Citation:
Alford M.H.,Girton J.B.,Voet G.,et al. Turbulent mixing and hydraulic control of abyssal water in the Samoan Passage[J]. Geophysical Research Letters,2013-01-01,40(17).