Open ocean regimes of relative dispersion
| Type | Article | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Date | 2005-06 | ||||||||
| Language | English | ||||||||
| Author(s) | Ollitrault Michel1, Gabillet Céline2, de Verdiere Alain Colin3 | ||||||||
| Affiliation(s) | 1 : IFREMER, Ctr Brest, Lab Phys Oceans, F-29280 Plouzane, France. 2 : Inst Rech Ecole Navale, F-29240 Brest, France. 3 : Univ Bretagne Occidentale, Lab Phys Oceans, F-29285 Brest, France. |
||||||||
| Source | Journal of fluid mechanics (0022-1120) (Cambridge univ. Press), 2005-06 , Vol. 533 , P. 381-407 | ||||||||
| DOI | 10.1017/S0022112005004556 | ||||||||
| WOS© Times Cited | 59 | ||||||||
| Keyword(s) | Taylor dispersion, Dispersion, Atlantic circulation, Particule pairs | ||||||||
| Abstract | As two fluid particles separate in time, the entire spectrum of eddy motions is being sampled from the smallest to the largest scales. In large-scale geophysical systems for which the Earth rotation is important, it has been conjectured that the relative diffusivity should vary respectively as D-2 and D-4/3 for distances respectively smaller and larger than a well-defined forcing scale of the order of the internal Rossby radius (with D the r.m.s. separation distance). Particle paths data from a mid-latitude float experiment in the central part of the North Atlantic appear to support these statements partly: two particles initially separated by a few km within two distinct clusters west and east of the mid-Atlantic ridge, statistically dispersed following a Richardson regime (D-2 similar to t(3) asymptotically) for r.m.s. separation distances between 40 and 300 km, in agreement with a D-4/3 law. At early times, and for smaller separation distances, an exponential growth, in agreement with a D-2 law, was briefly observed but only for the eastern cluster (with an e-folding time around 6 days). After a few months or separation distances greater than 300km, the relative dispersion slowed down naturally to the Taylor absolute dispersion regime. | ||||||||
| Full Text |
|