Trajectory Curvature As A Selection Criterion For valid Lagrangian Stochastic Dispersion Models |
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Authors: | John D Wilson Thomas K Flesch |
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Institution: | (1) Department of Earth & Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada |
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Abstract: | Among well-mixed multi-dimensional Lagrangian stochastic (LS) dispersion models, we observe that those in poorest agreement with observations produce spiralling trajectories, with an associated reduction in dispersion. We therefore investigate statistics of increments d ' to the orientation '= arctan(W'/U') of the Lagrangian velocity-fluctuation vector – as a possible means to distinguish the better LS models within the well-mixed class. Zero-spin models, having d' = 0, are found to provide best agreement with observations. It is not clear however, whether imposition of the zero-spin property selects (in conjunction with the well-mixed condition) a unique model. |
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Keywords: | Trajectories Turbulence Dispersion Diffusion Numerical models |
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