Shallow Water Acoustics英文电子书.pdf

Shallow-Water Acoustics Extracting a signal from noise can be complicated, and the presence of ocean inhomo- geneities and loud ships can fre- especially along a coastline filled with marine life, shipping quently scatter, jam, or mask the most lanes, undersea waves, shelves, and fronts that scatter interesting sounds. So, whether using sound. active or passive techniques, scientists are ultimately concerned with the physics of extracting a signal that William A. Kuperman and James F. Lynch propagates in a lossy, dynamic wave- guide from noise influenced by that uring the two world wars, oceanographers studied both same waveguide’s complexity. In that light, and consider- D shallow- and deep-water acoustics. But during the cold ing our still imperfect understanding of coastal oceanog- war, the research emphasis shifted abruptly to deep water, raphy, one can begin to appreciate shallow-water acoustics where the ballistic missile submarine threat lurked (see box as an interdisciplinary blend of physics, signal processing, 1). After the cold war, the onset of regional conflicts in coastal physical oceanography, marine geophysics, and even ma- countries shifted the focus again to shallow water. Those