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| Titel |
Local finite time Lyapunov exponent, local sampling and probabilistic source and destination regions |
| VerfasserIn |
A. E. Bozorgmagham, S. D. Ross, D. G. Schmale III |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2198-5634
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics Discussions ; 2, no. 3 ; Nr. 2, no. 3 (2015-05-28), S.903-937 |
| Datensatznummer |
250115177
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| Publikation (Nr.) |
 copernicus.org/npgd-2-903-2015.pdf |
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| Zusammenfassung |
| The time-varying finite time Lyapunov exponent (FTLE) is a powerful Lagrangian concept widely used for
describing large-scale flow patterns and transport phenomena.
However, field experiments usually have modest scales. Therefore, it is necessary to bridge between the
powerful concept of FTLE and (local) field experiments.
In this paper a new interpretation of the local FTLE, the time series of a FTLE field at a fixed
location, is proposed. This concept can practically assist in field experiments where samples are collected at a fixed location
and it is necessary to attribute long distance transport phenomena and location of source points to the
characteristic variation of the sampled particles. Also, results of this study have the potential to aid
in planning of optimal local sampling of passive particles for maximal diversity monitoring of assemblages of microorganisms.
Assuming a deterministic flow field, one can use the proposed theorem to (i) estimate the differential
distances between the source (or destination) points of the collected (or released) particles when
consecutive sampling (or releasing) is performed at a fixed location, (ii) estimate the local FTLE
as a function of known differential distances between the source (or destination) points.
In addition to the deterministic flows, the more realistic case of unresolved turbulence and low resolution
flow data that yield the probabilistic source (or destination) regions are studied. It is shown that
similar to deterministic flows, Lagrangian coherent structures (LCS) separate probabilistic source
(or destination) regions corresponding to consecutive collected (or released) particles. |
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