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On the use of random walk models with spatially variable diffusivity

Citation

Hunter, JR and Craig, PD and Phillips, HE, On the use of random walk models with spatially variable diffusivity , Journal of Computational Physics, 106, (2) pp. 366-376. ISSN 0021-9991 (1993) [Refereed Article]

DOI: doi:10.1016/S0021-9991(83)71114-9

Abstract

The random walk technique is commonly used to model diffusion in the environment. For a constant diffusivityK and model time-step δt, the random step should be chosen from a distribution with variance 2Kδt. However, ifK varies spatially, this choice of step leads to the accumulation of particles in regions of low diffusivity. This problem may be overcome either by the incorporation of an apparent advection velocity, or by transforming to a coordinate system in which the diffusivity is constant. The latter technique requires no immediate approximations, is applicable to any reasonable diffusivity field and is therefore the preferred approach. In this case, as with constantK, the random step should be chosen from a normal distribution, for reasons of both theoretical accuracy and computational efficiency. Three important aspects of model design are discussed: the selection of the random number generator, the time step and the total number of particles. © 1993 Academic Press, Inc.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
Author:Hunter, JR (Dr John Hunter)
Author:Phillips, HE (Dr Helen Phillips)
ID Code:39739
Year Published:1993
Web of Science® Times Cited:150
Deposited By:IASOS
Deposited On:2007-04-20
Last Modified:2013-01-09
Downloads:0

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