DOI: 10.1002/2017JC013316
Scopus记录号: 2-s2.0-85042554941
论文题名: Three-Dimensional Ageostrophic Motion and Water Mass Subduction in the Southern Ocean
作者: Buongiorno Nardelli B. ; Mulet S. ; Iudicone D.
刊名: Journal of Geophysical Research: Oceans
ISSN: 21699275
出版年: 2018
卷: 123, 期: 2 起始页码: 1533
结束页码: 1562
语种: 英语
英文关键词: ageostrophic velocities
; Southern Ocean
; water mass formation
Scopus关键词: adiabatic process
; ageostrophic flow
; Antarctic Intermediate Water
; boundary layer
; diabatic process
; equation
; flow velocity
; mesoscale motion
; model
; oceanic circulation
; subduction
; turbulent mixing
; vertical mixing
; water column
; water mass
; Antarctic Circumpolar Current
; Southern Ocean
英文摘要: Vertical velocities at the ocean mesoscale are several orders of magnitude smaller than corresponding horizontal flows, making their direct monitoring a still unsolved challenge. Vertical motion is generally retrieved indirectly by applying diagnostic equations to observation-based fields. The most common approach relies on the solution of an adiabatic version of the Omega equation, neglecting the ageostrophic secondary circulation driven by frictional effects and turbulent mixing in the boundary layers. Here we apply a diabatic semigeostrophic diagnostic model to two different 3-D reconstructions covering the Southern Ocean during the period 2010–2012. We incorporate the effect of vertical mixing through a modified K-profile parameterization and using ERA-interim data, and perform an indirect validation of the ageostrophic circulation with independent drifter observations. Even if horizontal gradients and associated vertical flow are likely underestimated at 1/4° × 1/4° resolution, the exercise provides an unprecedented relative quantification of the contribution of vertical mixing and adiabatic internal dynamics on the vertical exchanges along the Antarctic Circumpolar Current. Kinematic estimates of subduction rates show the destruction of poleward flowing waters lighter than 26.6 kg/m3 (14 ÷ 15 Sv) and two main positive bands associated with the Antarctic Intermediate Water (7 ÷ 11 Sv) and Sub-Antarctic Mode Waters (4 ÷ 7 Sv) formation, while Circumpolar Deep Water upwelling attains around 3 ÷ 6 Sv. Diabatic and adiabatic terms force distinct spatial responses and vertical velocity magnitudes along the water column and the restratifying effect of adiabatic internal dynamics due to mesoscale eddies is shown to at least partly compensate the contribution of wind-driven vertical exchanges to net subduction. © 2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114497
Appears in Collections: 气候减缓与适应
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作者单位: Istituto di Scienze dell'Atmosfera e del Clima, Consiglio Nazionale delle Ricerche, Roma, Italy; Istituto per l'Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche, Napoli, Italy; Collecte Localisation Satellite, Ramonville-Saint-Agne, France; Stazione Zoologica “Anton Dohrn”, Napoli, Italy
Recommended Citation:
Buongiorno Nardelli B.,Mulet S.,Iudicone D.. Three-Dimensional Ageostrophic Motion and Water Mass Subduction in the Southern Ocean[J]. Journal of Geophysical Research: Oceans,2018-01-01,123(2)