Stable Nocturnal Boundary Layers: A Comparison of One-Dimensional and Large-Eddy Simulation Models
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A one-dimensional model and a large-eddy simulation (LES) model are used to simulate the turbulence structure of a stably stratified atmospheric boundary layer. The results are compared with those obtained by Andren (1995) using a similar three-dimensional model and with experimental data. The one-dimensional model solves the fundamental equations of momentum, entropy and conservation of two scalars, and a diagnostic second-order closure model is used to determine the turbulent fluxes of the variables as well as the variances of the velocity and scalars. The two LES models differ in the definition of the sub-grid scale scheme. The comparison of the model results outlines the differences and the similarities between the three- and the one-dimensional simulations. Although the results of the two LES models differ in the description of some of the stable boundary layer turbulence features, it is shown that good agreement is obtained with local-similarity theory and experimental data. The differences between the results of three models relate to the stratification within the layer, the asymptotic value of the various turbulent variables for large stability regimes and their values close to the surface.
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