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Diapycnal Mixing in a Conceptual Model of the Atlantic Meridional Overturning Circulation

Bergen Open Research Archive

Show simple item record Marzeion, Ben eng Drange, Helge eng 2006-01-18T16:55:46Z 2006-01-18T16:55:46Z 2006 eng
dc.identifier.citation Deep Sea Research Part II: Topical Studies in Oceanography 53(1-2): 226-238
dc.identifier.issn 0967-0645 eng
dc.description.abstract A three-box model of the Atlantic Ocean is used to examine the influence different parameterisations of the diapycnal mixing may have on the large scale dynamics of the ocean circulation. Special emphasis is given to the northward volume and heat transports. The vertical diffusivity κ is taken in the general form κ ~ N −α , where N is the buoyancy frequency, and the parameter space 0 ≤ α ≤ 3 is explored. An imposed freshwater forcing of the northern high latitude box is used as a test case to investigate the behaviour of the model compared to similar types of sensitivity experiments carried out with, for instance, General Circulation Models. Four different solution states are identified, separated by three critical values of α. For small values of α, both heat and volume fluxes decrease with increasing freshwater flux. Increasing α leads first into a parameter domain where the transport of heat increases with increasing freshwater forcing, then at even higher α also the volume transport increases. Finally, a fourth state is found where strong advection of warm water leads to an increase of the northern box temperature, as opposed to cooling for small α. The behaviour of the critical values of α is discussed with respect to model dynamics and parameters. A subtle interplay between changes in the ther- mocline depth and the advective fluxes from the thermocline box into northern box, which both are modulated by diapycnal mixing, is found to be the key process in determining the behaviour of the model. Finally, the implications for modelling and understanding of basic features of the ocean circulation are discussed. en
dc.format.extent 334200 bytes eng
dc.format.mimetype application/pdf eng
dc.language.iso eng eng
dc.publisher Elsevier Science eng
dc.subject Oceanography eng
dc.subject Meridional oceanic circulation eng
dc.subject Modelling eng
dc.subject Vertical mixing eng
dc.subject Thermocline eng
dc.title Diapycnal Mixing in a Conceptual Model of the Atlantic Meridional Overturning Circulation eng
dc.type Journal article eng
dc.subject.nsi VDP::Matematikk og Naturvitenskap: 400 nob
dc.type.version SubmittedVersion eng
bora.journalTitle Deep Sea Research Part II: Topical Studies in Oceanography eng
bibo.volume 53 eng
bibo.issue 1-2 eng
bibo.pageStart 226 eng
bibo.pageEnd 238 eng
bibo.doi eng

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