Open ocean regimes of relative dispersion
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 D2 an...
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Cambridge University Press (CUP)
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ftoskarbordeaux:oai:oskar-bordeaux.fr:20.500.12278/77712 2023-05-15T17:33:17+02:00 Open ocean regimes of relative dispersion OLLITRAULT, Michel GABILLET, Céline COLIN DE VERDIERE, Alain 2005 https://oskar-bordeaux.fr/handle/20.500.12278/77712 https://doi.org/10.1017/S0022112005004556 en eng Cambridge University Press (CUP) 0022-1120 https://oskar-bordeaux.fr/handle/20.500.12278/77712 doi:10.1017/S0022112005004556 Sciences de l'ingénieur [physics]/Mécanique [physics.med-ph]/Mécanique des fluides [physics.class-ph] Article de revue 2005 ftoskarbordeaux https://doi.org/10.1017/S0022112005004556 2021-05-18T22:29:51Z 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 D2 and D4/3 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 (D2∼t3 asymptotically) for r.m.s. separation distances between 40 and 300 km, in agreement with a D4/3 law. At early times, and for smaller separation distances, an exponential growth, in agreement with a D2 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 300 km, the relative dispersion slowed down naturally to the Taylor absolute dispersion regime. 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 D2 and D4/3 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 (D2∼t3 asymptotically) for r.m.s. separation distances between 40 and 300 km, in agreement with a D4/3 law. At early times, and for smaller separation distances, an exponential growth, in agreement with a D2 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 300 km, the relative dispersion slowed down naturally to the Taylor absolute dispersion regime. Other/Unknown Material North Atlantic OSKAR Bordeaux (Open Science Knowledge ARchive) Mid-Atlantic Ridge Journal of Fluid Mechanics 533 |
institution |
Open Polar |
collection |
OSKAR Bordeaux (Open Science Knowledge ARchive) |
op_collection_id |
ftoskarbordeaux |
language |
English |
topic |
Sciences de l'ingénieur [physics]/Mécanique [physics.med-ph]/Mécanique des fluides [physics.class-ph] |
spellingShingle |
Sciences de l'ingénieur [physics]/Mécanique [physics.med-ph]/Mécanique des fluides [physics.class-ph] OLLITRAULT, Michel GABILLET, Céline COLIN DE VERDIERE, Alain Open ocean regimes of relative dispersion |
topic_facet |
Sciences de l'ingénieur [physics]/Mécanique [physics.med-ph]/Mécanique des fluides [physics.class-ph] |
description |
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 D2 and D4/3 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 (D2∼t3 asymptotically) for r.m.s. separation distances between 40 and 300 km, in agreement with a D4/3 law. At early times, and for smaller separation distances, an exponential growth, in agreement with a D2 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 300 km, the relative dispersion slowed down naturally to the Taylor absolute dispersion regime. 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 D2 and D4/3 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 (D2∼t3 asymptotically) for r.m.s. separation distances between 40 and 300 km, in agreement with a D4/3 law. At early times, and for smaller separation distances, an exponential growth, in agreement with a D2 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 300 km, the relative dispersion slowed down naturally to the Taylor absolute dispersion regime. |
format |
Other/Unknown Material |
author |
OLLITRAULT, Michel GABILLET, Céline COLIN DE VERDIERE, Alain |
author_facet |
OLLITRAULT, Michel GABILLET, Céline COLIN DE VERDIERE, Alain |
author_sort |
OLLITRAULT, Michel |
title |
Open ocean regimes of relative dispersion |
title_short |
Open ocean regimes of relative dispersion |
title_full |
Open ocean regimes of relative dispersion |
title_fullStr |
Open ocean regimes of relative dispersion |
title_full_unstemmed |
Open ocean regimes of relative dispersion |
title_sort |
open ocean regimes of relative dispersion |
publisher |
Cambridge University Press (CUP) |
publishDate |
2005 |
url |
https://oskar-bordeaux.fr/handle/20.500.12278/77712 https://doi.org/10.1017/S0022112005004556 |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
0022-1120 https://oskar-bordeaux.fr/handle/20.500.12278/77712 doi:10.1017/S0022112005004556 |
op_doi |
https://doi.org/10.1017/S0022112005004556 |
container_title |
Journal of Fluid Mechanics |
container_volume |
533 |
_version_ |
1766131737927090176 |