Scientia Marina, Vol 80, No S1 (2016)

Interaction of Mediterranean Water lenses with Antarctic Intermediate Water off Northwest Africa


https://doi.org/10.3989/scimar.04289.06A

Francisco José Electronica Machín
Department of Physics, University of Las Palmas de Gran Canaria , Spain

Josep L. Pelegrí
Institut de Ciències del Mar, CSIC , Spain

Abstract


Mediterranean Water lenses (meddies) in the eastern North Atlantic, north of the Canary Islands, appear to often have their salty and nutrient-poor core accompanied by relatively fresh and nutrient-rich waters on top. We describe several occurrences of freshwater halos and berets for meddies sampled north of the Canary Islands—with instrumented moorings, Argo floats and oceanographic cruises—and identify the source of these fresh anomalies as diluted Antarctic Intermediate Water (AAIW). We propose that this capping takes place off Northwest Africa, as the southward-advected meddy interacts with the northward-advected AAIW. This interpretation is consistent with a simple analysis of the relevant advective-diffusive time scales associated with the passage of meddies under a layer of AAIW, and suggests that meddies may be a mechanism for AAIW export far into the North Atlantic Ocean.

Keywords


meddies; Antarctic Intermediate Water; eastern North Atlantic

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References


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