Modelling large scale ocean circulation: the role of mixing location and meridional pressure gradients for the Atlantic overturning dynamics [Elektronische Ressource] / von Alexa Griesel

Modelling large scale ocean circulation:The role of mixing location andmeridional pressure gradients for theAtlantic overturning dynamicsDissertationzur Erlangung des akademischen Gradesdoctor rerum naturalium(dr. rer. nat.)in der Wissenschaftsdisziplin Physikalische Ozeanographieeingereicht an derMathematisch-Naturwissenschaftlichen Fakult at IUniversit at PotsdamvonAlexa GrieselPotsdam, im April 2005Wenn die Welt so einfach ware, dass wir sie verstehenwurden, dann wurden wir gar nicht existieren um sie ver-stehen zu wollen.(frei nach Emerson M. Pugh)AbstractDue to its relevance for global climate, the realistic representation of theAtlantic meridional overturning circulation (AMOC) in ocean models is a keytask. In recent years, two paradigms have evolved around what are its driv-ing mechanisms: diapycnal mixing and Southern Ocean winds. This workaims at clarifying what sets the strength of the Atlantic overturning compo-nents in an ocean general circulation model and discusses the role of spatiallyinhomogeneous mixing, numerical di usion and winds. Furthermore, the re-lation of the AMOC with a key quantity, the meridional pressure di erenceis analyzed.Due to the application of a very low di usiv e tracer advection scheme, arealistic Atlantic overturning circulation can be obtained that is purely winddriven.