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N.N.Andreyev Acoustical Institute. Russian Acoustical Society. II Session. ACOUSTICAL MEDIA MONITORING. Moscow 1993 ...
N.N.Andreyev Acoustical Institute

Russian Acoustical Society II Session

ACOUSTICAL MEDIA MONITORING

Moscow 1993

R E F E R E N C E S M u n к W. , W u n c h C. Ocean acoustic tomography: a scheme for large scale monitiring // Deep-sea Res. A. - 1979 - vol.26, N 2A.P.-123 - 161. 2 . Z a i t s e v V .Yu., N e c h a e v A .G,, О s t r o v s k y L.A. On the possibilities of ocean mode tomography.// Ocean acoustic. Edited by L.M.Brekhovskikh and I.B.Andreeva - M.: Nauka.-1989.-p.98-107. 3. T i к h о n о v A.n., G о n c h a r s к у A.V., S t e p a n о v V.V., V a g о 1 a A.G. Regularizating algorithms and a priory information. M.: Nauka, Fizmatgiz, 1983. 4. О к о т е 1 к о v a I . A . , S h e r e s h e v s ky I. A. Computation of the normal mode in a shallow medium. Gorky-1989, Inst. of Appl. Phys. of Russ. Acad, of Scien. 1.

M. S, Pekour, M. A. Lokoschenko SODAR OBDERVATIONS OR THE ATMOSPHERIC BUONDARY LAYER OVER THE CENTER OF MOSCOW

24-Hour sodar observations of the atmospheric boundary layer parameters and measurements of surface concentrations of several - atmospheric pollutants were taken in the center of Moscow from May 15 to June 15 (1990) and from January 30 to February 28 (1991) [1,2]. The type of thermal stratification, a mixing height, and occurence of intversion layers were determined every hour from the facsimile records of the vertical sodar. In addition, during the winter observations in 1991 sodar measurements of profiles for the three wind velocity components, the variance of the vertical components, and the structure characteristics of temperature fluctuations were also performed. The comparison of the sodar data with the surface concentrations of atmospheric admixtures (gas and aerosol) has shown that it is the wind velocity rather than ABL stratification type which affects the air pollution level. Figure 1 gives mean concentrations of soot C . and soot submicronal atmospheric aerosol for each type of

stratification

(neutral,

convertion,elevated

inversion and ground inversion) 129

for two seasons.

Figure 2 shows time variations of nitric dioxide concentration CNQ and reverse wind velocity 1/V. However, it should be noted that, without considering the characteristics of the sources of pollutants, a direct comparison of meteorological conditions and pollution concentrations cannot give a full insight into the mechanisln of pollution formations in Moscow air basin.

In extension of our experiments on the study of the wind field over Moscow, hourly sodar measurements of wind speed and direction profiles were performed in summer 1991 (July 1-17). Based on the data obtined, wind rises on different

heights, mean wind velocity profiles, mean diurnal variations of the Vertical wind velocity component and its variance were derived. The sodar data obtained in center of Moscow can be used to estimate mean meteorological conditions and their typical changes in the summer and winter periods and also to verify the models of pollutant propagation in the atmosphere. R E F E R E N C E S 1.

Control of Air Quality in Moscow. Part 1. Prepr. IAP USSR Acad, of Sc., No 1. Moscow 1991 2. Control of Air Quality in Moscow. Part 2. Prepr. IAP USSR Acad, of Sc., No 9. Moscow 1992

S. N. Kulichhov PARTIAL

REFLECTION OF ACOUSTIC MIDDLE ATMOSPHERE

PULSES

FROM

THE

This paper is concerned with the study of the possibilities of using an acoustic method of partial reflections of sound in t h e m i d d l e atmosphere at the 30-80 km heights. The acoustic method is bistatic; both a source and a receiver are placed on the ground surface at horizontal distances of several hundred of kilometers. Ground explosions of different energy are used as sources. The refractive acoustic method of sounding has been used earlier. D u e .to refraction sound rays from the ground sources can, at certain heights, turn to the ground. The data obtained in this case can be used to determine the effective sound speed stratification [1]. Since the turning conditions which essentially depend on the dominant wind derection in the upper atmospheric layers are unstable, such a method works only in specific seasons. It is suggested that the method of partial reflections should be used as a method of acoustic sounding of the middle atmosphere. Reflection of sound waves from stratified temperature and wind inhomogeneities in the middle atmosphere provides the basis for this method. Ideally (when the background is entirely absend), this method permits to determine the profiles of the effective sound speed which is higher than that at certain level in the middle atmosphere [2]. In actual practice the background level is high enough, therefore the employment of this method is expediently restricted to determination of some