Analysis of ocean turbulence using adaptive CVE on altimetry maps

It has been often argued that oceanic turbulence is similar to 2D turbulence; they share many properties and more particularly they seem to be driven by the dynamics of coherent vortices over large scales. For this reason, the application of techniques based on the extraction of coherent vortices as the Coherent Vortex Extraction (CVE) seems a natural choice for the description of ocean data. In this paper we will discuss on the properties of oceanic turbulence under the perspective of the Microcanonical Multifractal Formalism (MMF), and specifically for the description of altimetry data. We will see that MMF gives a good description of the geometry and statistical properties of altimetry data. We will show that a direct application of CVE on altimetry data has a rather low performance in comparison to other systems, which we justify as a consequence of the inhomogeneous character of ocean turbulence. We also show that a MMF-based separation criterion improves the standard CVE and allows to mitigate these problems. The results are discussed in the perspective of a cascade-based description of ocean turbulence.