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| Titel |
Multifractal intermittency of Eulerian and Lagrangian turbulence of ocean temperature and plankton fields |
| VerfasserIn |
L. Seuront, F. Schmitt, D. Schertzer, Y. Lagadeuc, S. Lovejoy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 3, no. 4 ; Nr. 3, no. 4, S.236-246 |
| Datensatznummer |
250001122
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| Publikation (Nr.) |
 copernicus.org/npg-3-236-1996.pdf |
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| Zusammenfassung |
| 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 ζ(q) 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 ω2 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. |
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