Effect of Rain on Underwater Noise Level

Abstract

The underwater noise due to precipitation has been measured in a small, shallow lake. The local wind speed, rain rate, atmospheric pressure, and noise level were recorded. It was found that the noise due to wind and the contribution from bottom boundary reflections over the period during which the data were recorded had a negligible effect. The data in the interval 300–9600 Hz have been analyzed in octave bands, and an estimate of the average noise level versus rain rate has been obtained. In comparison with the laboratory work done by Franz [J. Acoust. Soc. Amer. 31, 1080 (1959)] on splashes as a source of sound, our results show significantly higher noise levels and a difference in the shape of the noise-level-versus-frequency curve. However, the average rate of change in noise level with change in rain rate is of the same order of magnitude.