Propagation and Evolution of an Acoustic Gravity Wave in a Region of Wind Shear

By using the fundamental equations describing the evolution of an acoustic gravity wave (AGW) packet in an ambient wind,the variation characteristics of AGW’s essential parameters in a region of wind shear are studied.It is shown that the variations of wavelength,phase velocity and propagation direction depend on the vertical structure of the wind and also on the direction of the wave with respect to the wind.The variation manner of AGW kinetic energy is related to the variation in the spatial scale of AGW.For the upgoing gravity branch,an increase of kinetic energy of the wave packet is accompanied by an increase of the wavelength,while a decrease of the kinetic energy is accompanied by a decrease of the wavelength.For the upgoing acoustic branch,the situation is just opposite.It is also discussed that an AGW wavetrain propagates in the region of wind shear.It is shown that an increase of AGW energy density is accompanied by a decrease of intrinsic frequency,while a decrease of AGW energy density is accompanied by an increase of intrinsic frequency.