Titre :

Multifractal intermittency of Eulerian and Lagrangian turbulence of ocean temperature and plankton fields

Auteur(s) :

Seuront, Laurent [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Schmitt, François G [Auteur]
Laboratoire de Météorologie Dynamique (UMR 8539) [LMD]
Schertzer, D [Auteur]
Laboratoire de Météorologie Dynamique (UMR 8539) [LMD]
Lagadeuc, Y. [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Lovejoy, S. [Auteur]
Department of Physics [Montréal]

Titre de la revue :

Nonlinear Processes in Geophysics

Pagination :

236-246

Éditeur :

European Geosciences Union (EGU)

Date de publication :

1996

ISSN :

1023-5809

Discipline(s) HAL :

Physique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

Résumé en anglais : [en]

In this paper, we present evidence that intermittency of Eulerian and Lagrangian turbulence of ocean temperature and plankton fields is multifractal and furthermore can be analysed with the help of universal multifractals. ...
Lire la suite >In this paper, we present evidence that intermittency of Eulerian and Lagrangian turbulence of ocean temperature and plankton fields is multifractal and furthermore can be analysed with the help of universal multifractals. We analyse time series of temperature and in vivo fluorescence taken from a drifter in the mixed coastal waters of the eastern English Channel. Two analysis techniques are used to compute the fundamental universal multifiractal parameters, which describe all the statistics of the turbulent fluctuations: the analysis of the scale invariant structure function exponent <i>?</i>(<i>q</i>) and the Double Trace Moment technique. At small scales, we do not detect any significant difference between the universal multifiractal behavior of temperature and fluorescence in an Eulerian framework. This supports the hypothesis that the latter is passively advected with the flow as the former. On the one hand, we show that large scale measurements are Lagrangian and indeed we obtain for temperature fluctuations a <i>?</i><I>² </I>power spectrum corresponding to the theoretical scaling of a Lagrangian passive scalar. Furthermore, we show that Lagrangian temperature fluctuations are multiscaling and intermittent. On the other hand, the flatter slope at large scales of the fluorescence power spectrum points out that the plankton is at these scales a "biologically active" scalar.Lire moins >

Langue :

Anglais

Vulgarisation :

Non

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL