The Use of Doppler Radars for Studying the Turbulence of Air Masses in Clouds. The Use of Doppler Radars for Studying the Turbulence of Air Masses in Clouds.
A method for estimating the turbulent pulsations of the velocity of air masses in clouds has been proposed. This method is based on the spectra of scattered signals and makes use of the moment characteristics of the scattered signal spectrum and deviations of the characteristics from trend changes for estimating the shear characteristics of the air stream in terms of both the average speed and its spread.
For needs of aviation and fleet it is necessary to improve the methods for forecasting the weather, conditions of meteorological quantities (atmospheric pressure, wind, and air temperature), movements and evolutions of hazardous synoptic object, such as cyclones, their troughs with atmospheric fronts, anticyclones, ridges, etc.
Wind shear is the change of the wind vector (its speed and direction) per unit of distance. Wind shear is an indicator of the instability of atmosphere condition capable of causing the bumpy-air flight and at certain values of the wind shear it may endanger the safety of flights.
The vertical wind shear of more than 4 m/s per 60 m height is considered to be a meteorological phenomenon hazardous for flights.
At the first stage it had a descriptive character, when observations of reflections from meteorological formations and their classification were carried out, and the correlation between the reflections of different types and synoptic data was established.
The recognition of the nature of hydrometeors is a relatively new field of radiometeorology. In this connection the search for and investigation of the stable informative criterions is considered to be most topical direction of studies.
The majority of available studies involve the investigation of polarization spectral characteristics of signal backscattering and adsorption by hydrometeors for solving the inverse problem – determination of the spatial distribution of precipitation intensity, estimation of their potential hazard level.
In recent years the studies have appeared, where attempts are made to reconstruct the turbulent pulsations of air masses on the basis of the characteristics of scattered signal by using the movements of elementary scatterers
The present study proposes an approach to the analysis of turbulent pulsations, including those having the shear pattern, by using characteristics of the signal scattered by hydrometeors.