A Simple Analytic Model for Transport by Fluctuating Winds

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  • 1 Water and Air Resources Division, Civil Engineering Department, University of Washington, Seattle 98195
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Abstract

The statistical properties of airborne tracer concentrations, and the time-lagged correlation between concentration and wind velocity, are calculated from a simple model for the fluctuations in wind velocity. The mean concentration distribution thus calculated is compared with that obtained using the usual diffusivity formulation for transport, and the limitations on the diffusivity approximation discussed for various sources and sinks. It is shown that the model provides a method for calculation of the concentration statistics in the presence of velocity-dependent sources.

Abstract

The statistical properties of airborne tracer concentrations, and the time-lagged correlation between concentration and wind velocity, are calculated from a simple model for the fluctuations in wind velocity. The mean concentration distribution thus calculated is compared with that obtained using the usual diffusivity formulation for transport, and the limitations on the diffusivity approximation discussed for various sources and sinks. It is shown that the model provides a method for calculation of the concentration statistics in the presence of velocity-dependent sources.

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