Semi-adiabatic model of the deep stratification and meridional overturning

Timour Radko, Igor Kamenkovich

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

An analytical model of the Atlantic deep stratification and meridional overturning circulation is presented that illustrates the dynamic coupling between the Southern Ocean and the midlatitude gyres. The model, expressed here in terms of the two-and-a-half-layer framework, predicts the stratification and meridional transport as a function of the mechanical and thermodynamic forcing at the sea surface. The approach is based on the classical elements of large-scale circulation theory-ideal thermocline, inertial western boundary currents, and eddy-controlled Antarctic Circumpolar Current (ACC) models-which are combined to produce a consistent three-dimensional view of the global overturning. The analytical tractability is achieved by assuming and subsequently verifying that the pattern of circulation in the model is largely controlled by adiabatic processes: the time-mean and eddy-induced isopycnal advection of buoyancy. The mean stratification of the lower thermocline is determined by the surface forcing in the ACC and, to a lesser extent, by the North Atlantic Deep Water formation rate. Although the vertical small-scale mixing and the diapycnal eddyflux components can substantially influence the magnitude of overturning, their effect on the net stratification of the midlatitude ocean is surprisingly limited. The analysis in this paper suggests the interpretation of the ACC as an active lateral boundary layer that does not passively adjust to the prescribed large-scale solution but instead forcefully controls the interior pattern.

Original languageEnglish (US)
Pages (from-to)757-780
Number of pages24
JournalJ. PHYSICAL OCEANOGRAPHY
Volume41
Issue number4
DOIs
StatePublished - Apr 2011

Fingerprint

circumpolar current
stratification
thermocline
eddy
adiabatic process
deep water formation
North Atlantic Deep Water
western boundary current
meridional circulation
ocean
buoyancy
sea surface
advection
boundary layer
thermodynamics

Keywords

  • Atlantic Ocean
  • Gyres
  • Meridional overturning circulation
  • Southern Ocean

ASJC Scopus subject areas

  • Oceanography

Cite this

Semi-adiabatic model of the deep stratification and meridional overturning. / Radko, Timour; Kamenkovich, Igor.

In: J. PHYSICAL OCEANOGRAPHY, Vol. 41, No. 4, 04.2011, p. 757-780.

Research output: Contribution to journalArticle

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