MEASUREMENT OF THE SEABED REFLECTION COEFFICIENT IN SHALLOW WATER: A COMPARISON OF TWO TECHNIQUES

摘要

The seabed reflection coefficient is an important quantity required for the prediction of acoustic propagation and reverberation in shallow water and bottom-limited regions of the world's oceans. The angular and frequency dependence of the reflectivity also contains significant information about the seabed geoacoustic properties. Two reflection measurement techniques have been recently developed that share the common feature of spatially averaging over a relatively small region (of order the water depth). These "local" techniques have the ability to probe the spatial variability of the seabed to much finer scales than traditional methods. One of the techniques employs a towed broadband source and a single hydrophone receiver, the other technique employs ambient noise as the source and a vertical array of receivers. Reflection measurements at nearly co-located shallow water sites in the north Atlantic and the Straits of Sicily show good agreement despite completely different experimental approaches. The characteristics and limitations of each technique, indicate that they are mutually complementary.