DOI: 10.1038/ngeo2749
论文题名: Water-mass transformation by sea ice in the upper branch of the Southern Ocean overturning
作者: Abernathey R.P. ; Cerovecki I. ; Holland P.R. ; Newsom E. ; Mazloff M. ; Talley L.D.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 8 起始页码: 596
结束页码: 601
语种: 英语
Scopus关键词: brine
; buoyancy
; data assimilation
; estuarine front
; heat flux
; ice thickness
; mixing
; overturn
; sea ice
; snowmelt
; thermodynamics
; water mass
; Southern Ocean
英文摘要: Ocean overturning circulation requires a continuous thermodynamic transformation of the buoyancy of seawater. The steeply sloping isopycnals of the Southern Ocean provide a pathway for Circumpolar Deep Water to upwell from mid depth without strong diapycnal mixing, where it is transformed directly by surface fluxes of heat and freshwater and splits into an upper and lower branch. While brine rejection from sea ice is thought to contribute to the lower branch, the role of sea ice in the upper branch is less well understood, partly due to a paucity of observations of sea-ice thickness and transport. Here we quantify the sea-ice freshwater flux using the Southern Ocean State Estimate, a state-of-the-art data assimilation that incorporates millions of ocean and ice observations. We then use the water-mass transformation framework to compare the relative roles of atmospheric, sea-ice, and glacial freshwater fluxes, heat fluxes, and upper-ocean mixing in transforming buoyancy within the upper branch. We find that sea ice is a dominant term, with differential brine rejection and ice melt transforming upwelled Circumpolar Deep Water at a rate of ∼22 × 106m3s-1. These results imply a prominent role for Antarctic sea ice in the upper branch and suggest that residual overturning and wind-driven sea-ice transport are tightly coupled. © 2016 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/105947
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Scripps Institution of Oceanography, San Diego, CA, United States; British Antarctic Survey, Cambridge, United Kingdom; University of Washington, Seattle, WA, United States
Recommended Citation:
Abernathey R.P.,Cerovecki I.,Holland P.R.,et al. Water-mass transformation by sea ice in the upper branch of the Southern Ocean overturning[J]. Nature Geoscience,2016-01-01,9(8)