Long-range sound propagation in the northwestern region of the Pacific Ocean

Results of two experiments on long-range propagation of explosion-generated signals in the northwestern Pacific are analyzed. The propagation paths used in the two experiments substantially differ in both their hydrological characteristics and the conditions of signal reception. On the first path, the omnidirectional reception of explosion-generated signals is performed on the coastal shelf. The initial part of the 850-km-long path crosses the cold Kamchatka current and the continental slope. On the second path, the signals are received near the coastline of the Simushir island with a sea depth of more than 2000 m. The path crosses the Kuril-Kamchatka trough and the frontal zone formed at the boundary between the cold Kuril-Kamchatka current and the warm Kuroshio current. The intensity characteristics of the sound fields on the paths, the time structure of the signals, and the phenomena that arise when the path crosses the continental slope and the frontal zone are considered. The results obtained from analyzing the experimental data are compared with computer calculations.