Possibility of estimating radioactive fallout by modelling atmospheric processes.

The deposition of radioactive wastes like precipitation is formed as a result of the settling of long-lived explosion products from the atmosphere. If the parameters of the explosion (intensity, geometry, type of explosion and etc.) form a qualitative composition of radioactive products, then the effect of the meteorological influence are finally reduced to transport and change of the concentration of radioactive contamination.
Scattering of radioactive impurities is determined by stratification, turbulence and other parameters of the atmosphere, the direction and speed of their spatial distribution - the parameters of the direction and speed of the wind. Particles with sizes less than 10-12 microns moving at a speed identical to that of vertical movements (≈1cm /s) precipitate on the Earth's surface either in the turbulent motion of air masses (dry deposition), or by washing out sediments (wet and wet sediments) [1].
Assuming, in accordance with the idea of Taylor and Schmidt [2], that the process of turbulent diffusion is equivalent to the process of molecular diffusion.
Due to varying the value D between 0.5 and 1.3 in dependence on the climatic and landscape conditions, the average monthly values for climatological calculations will also have different and specific values which obey the same pattern [3].
Neglecting one of the solutions that will give rise physically incorrect result, we obtain the following expression for the excess concentration of radioactive particles in the atmosphere (more detailed see in [4])
As a result of pollution of the RF on a regional and global scale, it is necessary to use ground-based and remote methods and means of observation. The most effective use of radar remote sensing systems (RSS) in conjunction with optoelectronic equipment [5,6]. The most benefit of radar RSS is the absence of weather and time (day/night) restrictions [7] for getting information.
Radar means for detecting radioactive meteorological formation of anthropogenic nature are very different (active and passive radar). Monitoring principles of nuclear cycle enterprises is based on the appearance of anthropogenic release in the lower layers of the atmosphere which leads to a change in the physical parameters of the propagation medium, which creates a radar contrast and makes it possible to detect atmospheric inhomogeneity.
Experimental values of specific effective scattering area (abbreviated as ESR) of radioactive emissions are due to:
a) turbulent inhomogeneity of the air zone close to the exhaust pipe of NPP;
b) increased density of particulates (water droplets, aerosols, clusters and so on) so that radioactivity contributes to the formation of clusters which, consequently, affect the growth of large drops;
c) climatic and weather conditions, etc.
The analysis of the literature shows that for making studies targeted to creation of the satellite systems for the radar monitoring of radioactive releases it is necessary:
1. Creation of specialized multifrequency active and passive radars with increased energy potential;
2. Map of climatic and weather features of the area under study;
3. Data from meteorological satellites for comprehensive research;
4. Development of special algorithms for processing reflected radar signals [8].