**Atmospheric boundary layer** becomes the lowest layer. This is a region of the atmosphere, where the flow is strongly influenced by the properties of the Earth's surface. With contact with the surface occurs in this layer turbulence and intensive mixing. Energy flows (e.g.. heat) and matter (e.g.. water, CO2 and others) into the atmosphere depends directly on the flow and turbulence in the boundary layer. In the boundary layer of the atmosphere also leads to the emergence of some important meteorological phenomena, such as low cumulus clouds or even layered fog.

Understanding the physical processes in this layer is very important with regard to the study of dispersion and transport of atmospheric pollution. Description of the flow, however, is in the boundary layer greatly complicated thanks to the phenomenon of **turbulence**. This is one of the last outstanding chapters of classical physics, This is a problem, which is not yet final comprehensive physical description.

The flow in the boundary layer is influenced by a number of parameters, of which a number are difficult to mathematically express. To simulate and study specific cases are dealt two basic approaches - **numerical and physical modeling**. The basis of numerical modeling is the mathematical description, which leads to a system of nonlinear differential equations, Navier-Stokes. Numerical solutions of this system is a complex mathematical problem, which requires complex mathematical tools and powerful computing. Simpler models of the boundary layer also act as so-called. parameterization in models larger scale (serving for weather or climate simulation).

In some cases, however, the numerical modeling does not produce satisfactory results. Then accesses the physical flow modeling. This is most often done in wind tunnels. Experimental results are also often used as a reference when evaluating the accuracy of numerical models.

Numerical modeling is examined primarily on KMOP **using a numerical model CLMM** (Charles University Large-Eddy Microscale Model), which is intensively developed at the Department of. It is especially used for calculations pollution spreading in areas with complex geometries (e.g.. cities and industrial areas). It can also be used for theoretical studies of turbulence in the boundary layer stability under various conditions, including different options influence the Earth's surface.

Physical modeling is carried out mainly by students and PhD students in collaboration with KMOP **FW ASCR**. Among the most studied topics include the spread of pollution in the cities and the structure of turbulent flow over a rough surface.

These two above mentioned groups work together on projects, which include experiments and numerical simulations, among other such. GET project 535412 "Detection of process ventilation idealized urban pollution for various geometric arrangement". In addition, we are involved in such. the European cooperation project COST ES1006 dealing with the uncertainties of model results and the proper use of models for the spread of hazardous substances emergency.

The topic of the atmospheric boundary layer, turbulence and the spread of contamination is devoted several lectures in basic course of Meteorology (Physics of the boundary layer, Turbulence, Transport pollution in the atmosphere) a jedna přednáška v programu užité meteorologie (Applied physics of the boundary layer). Also currently in this area given 4 dizertační a 1 thesis.