The propagation of an acoustic pulse in a near-ground atmospheric waveguide

A wave theory of propagation of an acoustic pulse in a moving stratified atmospheric layer above the ground with a finite impedance of an underlying ground surface is developed. The shapes of acoustic signals in a near-ground atmospheric waveguide, which are formed due to temperature inversion and a vertical shear of the wind velocity, are calculated based on this theory. These signals are compared with those measured during the experiments where vertical profiles of the wind velocity and temperature in an atmospheric boundary layer have been continuously controlled using a sodar, a temperature profile meter, and acoustic anemometers or thermometers mounted on a 56-meter-high mast. The joint action of a near-ground acoustic waveguide, the impedance of the underlying surface, and a vertical layered structure of the boundary atmospheric layer on a signal shape far from the acoustic source are studied.