Long time-base observations of surf noise

A year of surf noise observations in the very near shore region of La Jolla Shores beach are presented. Ambient sound levels and surface wave height w ere recorded for 9 min every hour from July 1997 through June 1998 at a mon itoring station located 360 m seaward of the beach in 8-m deep water. Sound segments that were dominated by the noise from breaking surf formed the ba sis of a correlation analysis between surf noise level and wave height, wav e period, wind speed, and mean water depth. The analysis shows that surf no ise is primarily determined by wave height, and scales approximately with t he wave height squared. The surface wave energy flux onto the bench also sc ales with wave height squared, leading to the conclusion that the conversio n of the mechanical energy of the surface wave field into noise energy is a pproximately constant. In fact, the ratio of noise energy to surface wave e nergy flux varies by up to a factor of 3 over the range of energy fluxes co nsidered (100-3000 W per m). (C) 2000 Acoustical Society of America. [S0001 -4966(00)01602-7].