Observation of Small Scale Shelf-Trapped Dipolar Vortices near the Eastern Sicilian Coast

Abstract

In this short note we describe and discuss an unusual field of small-scale baroclinic vortices, observed through CTD casts in a small geographical zone (?6 ? 9 km) near the East Sicilian coast of the Ionian Sea (Eastern Mediterranean). The space dimension of these vortices is ?2 km in the horizontal plane while the Rossby internal radius of deformation is Rd ≈ 7 km; the vertical dimension is ?80 m; the velocities reach ?0.2 m s?1 and the Rossby number ? ? 1. Their relation with known theoretical models, in particular with hetons, shelf-break trapped mushrooms and baroclinic modons, is briefly discussed.