|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|
|WOS© Times Cited||53|
|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.|
Ollitrault Michel, Gabillet Céline, De Verdiere Alain Colin (2005). Open ocean regimes of relative dispersion. Journal of fluid mechanics, 533, 381-407. Publisher's official version : https://doi.org/10.1017/S0022112005004556 , Open Access version : https://archimer.ifremer.fr/doc/00000/456/