V. A. Zinichev

Radio-acoustic sounding of the troposphere using short radio waves

Abstract The possibility of constructing radio-acoustic sounding system (RASS) for the troposphere and lower stratosphere is discussed in detail. The design parameters for a RASS comprising a short radio wave radar and a powerful low-frequency acoustic antenna are presented. Factors that influence the accuracy of the temperature profile measurements are discussed. Temperature profiles measured with RASS and radiosondes are compared. Under favourable weather conditions sounding heights up to 4-5 km were attained

Study of wind characteristics at heights of 200 to 800 meters using a decimeter sodar

The results of the experiment carried out in July–August 1997 using a two-position sodar are reported. Different types of intensity and spectrum variations of scattered acoustic signals have been obtained. The possibilities of using the sodar for the study of atmospheric turbulence and search of signals caused by “Fresnel” scattering from “plane” irregularities are discussed.

Study of small variations of troposphere parameters by the radioacoustic sounding method

We consider a method based on the study of signal amplitude and phase variations in the radioacoustic sounding (RAS) of the atmosphere for the diagnostics of dynamical and wave processes in the troposphere. We give experimental data on phase variations of the RAS signal from scan to scan in daytime and nighttime sessions. Variations of the signal phase with characteristic time greater than 40 min are likely due to the passage of internal gravity waves (IGW) through the sounding region. The experimental data are in good agreement with the results of computer simulation of IGW propagation.

THE ROLE OF ATMOSPHERIC TEMPERATURE GRADIENTS AND WINDS FOR ESTIMATING THE ENERGY POTENTIAL OF RADIO-ACOUSTIC SOUNDING SYSTEMS

We present the theory of radio-acoustic sounding (RAS) of the atmosphere allowing for the dependence on temperature, altitude, and wind. For the case of a linear temperature profile, we obtained expressions for the received signal power. Since the acoustic wave front differs from the sphere if the temperature gradient is allowed for, we can introduce the notion of projector (Fresnel) and Fraunhofer regions. In the Fresnel region, the size of the diffraction spot on the earth is determined by radar antenna dimensions and the received signal power is proportional to z−2. In the Fraunhofer region, the spot size is greater than the antenna dimensions and the power is proportional to z−6. The existing RAS facilities work in the projector region. This can be used as a basis for developing a new method of diagnostics of a large-scale inhomogeneous atmospheric structure, including wave disturbances.

Operating decameter RASS near Nishny Novgorod and perspectives for far radio-acoustic sounding using the Sura HF-radar

Abstract An investigation of a tropospheric radio-acoustic sounding system (RASS) on the basis of the powerful HF-heating facility, ‘SURA’ is proposed. The specifications of a RASS for regular temperature profile measurements up to a height of 15 km, where the main processes of energy exchange take place, are discussed. Temperature profile data measured with an existing low-frequency prototype are presented. They are for a height of up to 6 km and the time resolution is about a few minutes. Differences between the RASS and sonde profiles typically do not exceed 1 K.