Underwater noise due to rain—Open ocean measurements

Abstract

Measurements of underwater noise produced by rain over the open ocean were made at a site some 1 km off Ucluelet on the west coast of Vancouver Island, British Columbia, Canada. A hydrophone was placed near the bottom in 55 m of water in the path of the prevailing eastward moving Pacific storm systems. The spectral noise-level dependence on rain rate between zero and 20 mm/h was determined for various frequencies and sea states. A straight line, least-squares fit to the sample values of spectral level plotted against the log of rain rate was found to best represent the relationship. Representative rain noise spectra for various rain rates and sea states were derived.

The seismic signature of rain

“…In agreement with the results of Olhovich (1964) and consistent with marine studies (Scrimger et al 1989), most of the rain noise occurs at frequencies above 80 Hz. This implies that its removal may be as simple as the application of a band-pass filter.…”

Practical Wind Speed and Rain Rate Prediction from Underwater Noise.

“…iv. Nystuen Figure 11 shows data from this study plotted with Nystuen, Scrimger et al, Nystuen and Farmer, and Scrimer et al<4 15,16 , 21 Nystuen recorded an extraordinary rain rate ot 260 mm/hr in a lake. His hydrophone, in 8 m of water, recorded noise levels gireater than any other rain study.…”

“…Scrimger et al, followed with more open ocean work. 21 Their recordings were off Vancouver Island in British Columbia, Canada. They deduced a relationship between noise level and rain rate for various sea states and frequencies.…”

The Impact of Drops on Liquid Surfaces and the Underwater Noise of Rain

“…Publication of this result was however delayed until 1986. In 1984 Scrimger and coworkers (who had been in contact with both Nystuen and Farmer) made similar measurements in Canada with analogous results and were 582 PROSPERETTI & O~;UZ the first to report the discovery in the open literature (Scrimger 1985;Scrimger et al 1987Scrimger et al , 1989. The remarkable results obtained by these investigators can be illustrated with reference to Figure 3 (from Scrimger et al 1987).…”