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

• Published in: Scientia Marina
• Main Authors: Francisco José Electronica Machín, Josep L. Pelegrí
• Format: Article in Journal/Newspaper
• Language: English
• Published: Consejo Superior de Investigaciones Científicas 2016
• Subjects: meddies; antarctic intermediate water; eastern north atlantic; Aquaculture. Fisheries. Angling; SH1-691; Antarctic; Antarc*; North Atlantic
• Online Access: https://doi.org/10.3989/scimar.04289.06A; https://doaj.org/article/92c2959f84864772a2dd4a74d9507560

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.