nikov, V. I. Boiko, I. V. Sh:tm:min, and O. V. Andreev UDC 504.054.001.5;504.064The possibility of using pulsed microwave radars for remote monitoring of radioactive contamination of air above nuclear power plants and nuclear-chemical production plants has been under discussion in the last few. years [I, 2]. Such stations are mainly employed for navigational support for airplanes, and in the process of location they can register reflected radio signals from clouds, rain, snow, and smoke above power plants, steam above cooling towers, and other atmospheric formations. Therefore, in developing methods for monitoring of atmospheric contamination it is of interest to employ existing radars for independent monitoring of industrial emissions.It is well known that monitoring problems are extremely complicated and expensive to solve. This is especially true for remote monitoring of radioactive emissions by radio measurement methods --microwaves are reflected mainly by free electrons formed by ionization of air and their density at atmospheric pressure is low even under the conditions of strong emission. Moreover, radioactive substances are ordinarily emitted together with a large quantity of warm air and aerosols, reflections from which can be many times greater than the reflection from ionization traces. For this reason, to substantiate the radar method of monitoring technological and accidental emissions of radionuclides into the atmosphere it is important to separate the useful signal due to radiation agairt~t the background of accompanying reflections. This requires more complete theoretical and experimental investigations of the processes involved in the formation of an ionized region and its interaction with electromagnetic waves.In the present paper we present some results of numerical calculations of the spatial distribution of radionuclides at the exit of a ventilation pipe of a reactor, analysis of their interaction with air, and formation of a weakly ionized plasma at atmospheric pressure, as well as data from radar observations of the air space above the industrial zone of a Siberian chemical plant (SCP) and IRT-T of the Scientific-Research Institute of Nuclear Physics at the Tomsk Polytechnical Universi-

Methods for determining the height of sea waves, which are relevant for maritime navigation, have been investigated. The measurement of the height of sea waves by the method of radar sounding by polarization-modulated signals is considered. The energy and spectral characteristics of the radar signal reflected by the sea surface at low angles of incidence are described. An algorithm for calculating the average wave height based on the results of measuring the polarization anisotropy of the specific effective scattering surface of the sea area is considered. The relation of the average frequency of the amplitude fluctuations of the reflected radar signals with the sea waves is given. The spectral characteristics of radar signals reflected by the sea surface when irradiated with polarization-modulated signals are analyzed. The procedure for forming an effective statistical estimate of the average wave height based on the results of spectral measurements is considered. The errors of the generated estimates of the wave height associated with the measurement errors of the polarization anisotropy of the effective scattering surface and the average frequency of the envelope of the amplitude fluctuations caused by the Doppler effect are analyzed. The results of experimental measurements of the spectra of the amplitude fluctuations of the envelope of the reflected signals at different states of the sea surface are presented. The analytical dependence of the polarization anisotropy of the effective sea scattering surface on the irradiation angle relative to the wave propagation direction is given. A comparison of estimates of the height of sea waves obtained from radar sounding and meteorological observation data is carried out.

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