Rankine-like eddies in the ocean: importance and detection
The general thinking is that ocean eddies are Gaussian-like instead of Rankine-like. We will show however that in several oceanic regions, such as around the Canary Islands or in the Gulf of Tanhuentepec (Mexico), eddies are initially Rankine-like and evolve towards Gaussian type. Gaussian-like vortices have a Gaussian distribution of vorticity, smooth shear zones at their periphery, their azimuthal velocity does not vary linearly and anticyclones are unstable. On the contrary, Rankine-like vortices are on solid body rotation, have strong shears at their periphery, the azimuthal velocity field varies linearly and anticyclones are stable. A simple way to detect both vortices is through hydrographic field anomalies. In Rankine-like vortices, anomalies do not have a well-defined center and gradients increase towards the periphery. In Gaussian type vortices, anomalies have a clear center with gradients increasing toward the vortex center. In Rankine vortices there is a strong diapycnal mixing at their periphery that enhances primary production.
