Source Level Estimation of the Snapping Shrimp Sound Observed in the Coastal Sea

Abstract

The ambient noise in the ocean shows very different dependences on marine life as well as wind, rainfall, and shipping. The sources of ambient noise in the deep ocean are clearly identified from the summary of a large amount of data measured in the 1940s. According to this summary, the main sources of ambient noise are distant shipping and ocean surface wind. The ambient noise in the coastal sea is more complex than the noise in the deep ocean owing to the breaking waves in the surf zone and the marine life as well as the shipping and wind. Since the biological noise due to the marine life has very high diurnal dependence and seasonal variation, it has a greater effect on ambient noise than others. In particular, it is well known that the sounds of dolphins and snapping shrimp affect sonar ping signals. In the coastal sea, where snapping shrimps live, their sounds always exist with ambient noise such as the noise due to shipping and wind. Therefore, the sound of snapping shrimps can effect ambient noise and sonar detection performance more than the sound of dolphins. For this reason, many researchers have measured and analyzed the snapping shrimp sound. In this study, we estimated peak to peak sound pressure source level of the snapping shrimp sound observed in the coastal sea.