Analysis of underwater rain noise from shallow water ambient noise measurements in Indian seas

Abstract

<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-gb;mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">Ocean ambient noise data were collected in shallow waters of Indian seas. The surface parameters like wind speed, wind direction and rainfall rate were measured by a buoy mounted anemometer and precipitation type rain gauge. On retrieving and analysing the ambient noise data sets, heavy rainfall noise was observed in the power spectral density over a frequency band from 2-7 kHz. Ambient noise intensity in the acoustic data correlate well with the rainfall rates recovered from the rain gauge. This paper presents the work carried out on the sea surface noise coherence and vertical directionality pertaining to rain in shallow waters of Bay of Bengal and Arabian Sea. In Indian seas so far no research work has been carried out on analysing the rainfall noise coherence and directionality and this is the first such study which will be useful further for deriving rain parameters such as rain drop size, number of drops, etc.</span>