Keywords: mixing height, atmospheric boundary condition, natural radioactivity, alpha spectroscopy, polonium concentration, atmospheric turbulence, diurnal variation, acoustic sodar instrumentation, air pollution, air quality, dispersion modelling
Diurnal variation of the mixing-layer height and polonium concentration in the air
The Mixing Height (MH) is one of the most important parameters that characterise the range of the atmospheric turbulence. This parameter shows characteristic diurnal variation but cannot be measured immediately. Therefore, it is evaluated indirectly by measuring other quantities. The measurement of radon concentration in the atmospheric air is one of the methods using natural occurring radioactivity to fulfil this task. However, for various reasons, such measurements can be difficult because the natural level of radon concentration in the atmospheric air is rather low. The newly developed method described in this paper relies on the measurement of polonium 218Po concentration in the air and was examined during measurement campaigns performed in hot seasons. The acoustic sodar instrumentation was chosen as a reference method. As a result, the statistical model was developed to define the MH and the obtained results made it possible to find statistically significant relation between concentration of 218Po in the air and this parameter.