| 摘要 |
PURPOSE:To measure remotely the temperature under water at a proper position on a waterway by transmitting an impulsive sound wave from a transmitter so that the wave crosses the directions of receivers at specific depth, and calculating the difference in the propagation time of the sound wave to the receivers. CONSTITUTION:The transmitter B transmits sound wave to under water, and a receiver A directs a reception beam in a specific direction to receive its reflected sound wave. The impulsive sound wave sent by the transmitter B while reflected partially and irregularly propagates toward intersections C and D of the transmitter's and receiver's beams. The sound wave received by the receiver A is only the reflected sound wave which is reflected by scattered particles at the intersection D and propagates toward the reciever A. The same result is obtained in a receiver A'. The mean sound speed within the distance ED, i.e. difference in depth between the points C and D is calculated from the difference in arrival time of the reflected waves at A and A', and the water temperature in the water depth layer ED is found in a sound speed-water temperature variation table. |
