Abstract
The sound channel will be formed in accordance with the wind current and temperature distribution. When the sound ray has the same direction of the propagation with the jet stream, the velocity minimum in the vertical distribution of the sound velocity exists on about 23km in height. And if the sound ray radiating from the ground, it is refracted at about 13km in height and then comes back to the ground. When the sound ray has opposite direction to wind stream, the velocity minimum of the vertical sound velocity distribution will occur at the altitude of 12km.
