Connection between encounter volume and diffusivity in geophysical flows

TitleConnection between encounter volume and diffusivity in geophysical flows
Publication TypeJournal Article
Year of Publication2018
Authors, Smith SGL, Pratt L.J
JournalNonlinear Processes in Geophysics
Date Published2018/04
Type of ArticleArticle
ISBN Number1023-5809
Accession NumberWOS:000429124000001
Keywordsatlantic; dispersion; dynamics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; ocean; patterns; statistics; transport

Trajectory encounter volume - the volume of fluid that passes close to a reference fluid parcel over some time interval - has been recently introduced as a measure of mixing potential of a flow. Diffusivity is the most commonly used characteristic of turbulent diffusion. We derive the analytical relationship between the encounter volume and diffusivity under the assumption of an isotropic random walk, i.e., diffusive motion, in one and two dimensions. We apply the derived formulas to produce maps of encounter volume and the corresponding diffusivity in the Gulf Stream region of the North Atlantic based on satellite altimetry, and discuss the mixing properties of Gulf Stream rings. Advantages offered by the derived formula for estimating diffusivity from oceanographic data are discussed, as well as applications to other disciplines.

Short TitleNonlinear Process Geophys.
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