相模湾における多経路伝搬音波の伝搬損失と変動の評価

抄録

In monitoring of water mass structure in mid-deep water using acoustic multipath propagation, sound propagates reflecting at surface and bottom. In this case, the acoustic reflection characteristics of surface and bottom such as reflection loss and stability are important determinants of sound field. In this paper, we examine the reflection loss of the sea bottom and stability in Sagami Bay from the sound transmission experiment data. The rays which reflect at surface and/or bottom once are identifiable in a predicted sequence and almost stable in 50 ms. Comparing the measured and calculated data, we estimate the average bottom reflection loss to be about 12 dB at 4.1 kHz with grazing angle of 13°. We consider that from these rays measurement of the perturbation of travel time corresponding to the mid-deep ocean fluctuations can be made