Intraseasonal variability in the southwestern and central tropical Atlantic Ocean [Elektronische Ressource] / vorgelegt von Karina von Schuckmann

Intraseasonal variability in the southwestern andcentral tropical Atlantic OceanDissertationzur Erlangung des Doktorgradesder Mathematisch-Naturwissenschaftlichen Fakultatder Christian-Albrechts-Universitatzu Kielvorgelegt vonKarina von SchuckmannKiel, September 2006Referent/in: Priv.-Doz. Dr. P. BrandtKorreferent/in: Prof. Dr. C. B oningTag der mundlic hen Prufung: 06.11.2006Zum Druck genehmigt: Kiel, den 06.11.2006Der Dekan Prof. Dr. J. GrotemeyerAbstractVarious kinds of intraseasonal variability (ISV) exist in the oceans which have recently beenobserved in many locations surrounding the tropical Atlantic Ocean. Their forcing mecha-nisms can involve di eren t dynamic processes, i.e. intraseasonal wind uctuations, internalocean processes or remote forcing. In this study, current measurements from mooring sitesclose to the western boundary in the southern hemisphere and at the equator in the cen-tral basin are analyzed which reveal signals at intraseasonal periods. Basinwide altimetermeasurements as well as results from two numerical model simulations with varying surfacewind forcing are applied in order to clarify the dynamic processes essential for the ob-served intraseasonal signals. It is shown that in the tropical Atlantic two key processes leadto the generation of uctuativ e energy at intraseasonal periods: barotropic and baroclinicinstability.