Impurity propagation in urban area with complex surface relief

The paper presents a new approach to study of the pollution process in systems with complex surface relief. As a case study, laboratory modeling of impurity transport in an idealized urban landscape was considered. As an experimental model, we used a three-dimensional layout of the central part of Perm city (the area of five square kilometers) at the scale of 1:4000. The model was placed in a watertight container with water, and aqueous solution of sodium chloride was used as an admixture. Estimation of the governing parameters for the urban area was done using typical values of turbulent viscosity for an urban area without mean circulation. Experimental modeling provides qualitative description of the air pollution by a mixture of carbon dioxide/air from heavy traffic. It is shown that the terrain features play a significant role in the process of the pollution spreading. The admixture tends to fill the lowest areas of the model. At the same time, the presence of buildings prevents the impurity transport. A qualitative comparison of experimental results and in-situ observations is presented.