PRELIMINARY STUDY OF LOW FREQUENCY SHALLOW WATER AMBIENT NOISE IN NARRAGANSETT BAY, R.I.
RHODE ISLAND UNIV KINGSTON NARRAGANSETT MARINE LAB
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Continuous recordings of the shallow water 25 cps octave vertical noise component and certain environmental variables were obtained every other day during the month of March, 1961. The analysis of these data shows that significant associations exist between noise and tidal slope, wind speed, and wave height. In addition, when the noise level data are averaged according to the hour of the observation, a cyclicity is evident which has a twelve-hour period and is phased so that the noise peaks are positioned at approximately noon and midnight. A twelvehour cyclicity is also apparent for the hourly averages of the tidal level, but not the tidal slope. Cyclicity of the tidal level averages suggests that the cyclic noise variation is the result of tidal influences. Lack of cyclicity in the tidal slope averages contradicts this explanation and favors the belief that the noise level in this frequency band may be displaying a diurnal variation comforming with a similar result first reported by Wenz and Linnette in November, 1960. Because of the strong tidal influence on noise in this octave, it was not possible to either accept or reject the hypothesis of a diurnal noise variation. Author