Two approaches to describing the turbulent exchange within the atmospheric surface layer

Abstract

Two two-dimensional models that describe the interaction of an air flow with a heterogeneous vegetation cover within the atmospheric surface layer are presented. These models differ in the closure techniques used to obtain approximate solutions of the averaged system of the Navier−Stokes and continuity equations and also in the approaches applied to describe the interaction of the air flow with elements of vegetation. The first model is based on the one-and-a-half-order closure scheme and the interaction of an air flow with elements of vegetation is described using the viscous drag force. The second model uses the first-order closure scheme and the distribution of the wind velocity field near the boundaries between different vegetation communities is simulated by the theory of contrast structures (CSs). We also present the results of the numerical experiments to compare the developed models with respect to their ability to describe the wind-velocity field within the atmospheric surface layer above the different forms of vegetation cover heterogeneity, such as a forest belt and clear-cut areas.