Estimation of turbulent diffusion coefficients from decomposition of Lagrangian trajectories
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Authors
Ivanov, L.M.
Chu, P.C.
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Date of Issue
2019
Date
2019
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Elsevier
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Abstract
A new technique is proposed for estimating turbulent diffusion coefficients (in the present paper turbulence is assumed to be homogeneous) which is based upon wavelet decomposition which separates the mean and osillatory (random) parts of Lagrangian trajectories. A one-dimensional discrete Daubechies wavelet transform is applied to decompose Lagrangian trajectories into components, each of which corresponds to a specific time scale τ. Diagonal diffusion coefficients are calculated from equations obtained from a combination of classical mixing length theory and general ideas from a theory of turbulent diffusion. Non-diagonal diffusion coefficients are found using the classical theory of the first passage boundary. The technique is illustrated through the analysis of twelve trajectories of RAFOS floats along the California-Oregon coast, twenty surface drifters de- ployed in the California Current System, and forty-five surface drifters deployed in the Black Sea in 2000–2002. The approach is compared with the well-known Davis (1991) approach in applications to the Black Sea drifters and single float trajectories along the California-Oregon coast.
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Article
Description
The article of record as published may be found at https://doi.org/10.1016/j.ocemod.2019.03.011
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Oceanography
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Citation
Ivanov, L.M., and P.C. Chu, 2019: Estimation of turbulent diffusion coefficients from decomposition of Lagrangian trajectories. Ocean Modelling, 137, 114-131.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.