Reflection of Sound Waves from the Stratosphere over India in different seasons of the year.

Propagation of sound in the stratosphere in different seasons was studied over India from a series of explosions made from two centres in reserved forests. Seven stations along the line joining the explosion centres and two perpendicular to it recorded the sound waves. From the time – distance graphs, times of arrival of sound waves at varians receptor points in different seasons were tabulated. Though there are several layers from which the sound got reflected, there existed a dominant layer in the stratosphere reflecting sound waves all the year round. Trajectories of sound waves indicate that the sound waves take two to three different paths as evidenced by the delayed arrival at recording stations. From the maximum height of sound trajectories at the corresponding height, at different stations and in different seasons were calculated with which lapserates in stratosphere were evaluated. There is no marked seasonal variation of the height of temperature inversion layer though its depth varied in different seasons being thinnest in summer.