Mixing and Dynamics of the Mediterranean Outflow

• Main Author: Baringer, Molly O.
• Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
• Format: Text
• Language: English
• Published: 1994
• Subjects: Physical and Dynamic Oceanography; *OCEAN CURRENTS; *MEDITERRANEAN SEA; *MIXED LAYER(MARINE); *GIBRALTAR STRAIT; TEST AND EVALUATION; STRESSES; ANOMALIES; THESES; DEPTH; MASS FLOW; FROUDE NUMBER; ENTRAINMENT; INSTABILITY; HYDROGRAPHIC SURVEYING; ADVECTION; WATER MASSES; NORTH ATLANTIC OCEAN; HEAT FLUX; SALINITY; STRAITS; PLUMES; MIXING; BATHYMETRY; VORTICES; MODELS; DENSITY; GULFS; *CADIZ GULF; KELVIN HELMHOLTZ INSTABILITY; VORTICITY; XCP(EXPENDABLE CURRENT PROFILER); North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA279803; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA279803

Hydrographic and XCP data taken during the Gulf of Cadiz Expedition in September 1988 are analyzed here to understand the mixing and dynamics of the Mediterranean outflow from the Strait of Gibraltar. Rapid entrainment of fresh North Atlantic water prevents the flow from reaching abyssal depths in the North Atlantic despite its large initial density anomaly. Dynamical ideas about mixing and stress are tested by examining the evolution of momentum and density as the flow adjusts. The flow is found to be unstable to Kelvin-Helmholtz instability in regions where intense mixing occurs. Evaluation of the cross-stream momentum balance shows the importance of advection as the flow makes a 90 degree inertial turn after exiting the Strait. The downstream momentum residuals indicate that large stresses disrupt this rapidly achieved geostrophic balance and enable the flow to cross isobaths. The intense mixing observed suggests rates of entrainment three orders of magnitude larger than typical rates of Ekman pumping in the open North Atlantic. A simple numerical model developed by Price and Baringer (1993) is used to test these dynamical concepts. The model predicts the evolution of the bulk properties of the Mediterranean outflow using a Froude number dependent entrainment Turner, 1986). Mixing, Overflow, Plume.