CONTENTS 



INTRODUCTION . . . page 5 

 METHODS . . . 8 

 RESULTS . . . 13 

 CONCLUSIONS . . . 23 



ILLUSTRATIONS 



1 Sea-noise spectra for various sea states . . .page 6 



2 Ambient -noise spectra, summarizing results and conclusions 



concerning spectrum shape and level and probable sources 

 and mechanisms of the ambient noise in various parts of 

 the spectrum between 1 c/s and 100 kc/s . . . 7 



3 Portion of wind-wave analysis from Fleet Numerical Weather 



Facility, Monterey, California, showing wave-height 

 contours . . . 8 



4 Typical sections of records of broadband ambient -noise 



levels . . . 10 



5 Distribution of maximum wave heights . . . 12 



6 Variation with frequency of coefficient of correlation between 



sound pressure spectrum level and cumulative maximum 

 wave heights, all stations . . . 14 - 15 



7 Monthly average sound pressure level at 20-c/s midband 



frequency, and monthly average local wave height . . .16 



8 Variation with frequency of coefficient of correlation between 



sound pressure spectrum level and cumulative maximum 

 wave heights for periods of highest and lowest frequency 

 of occurrence of 20-c/s signal, all stations . . .17 - 18 



9 Variation with frequency of coefficient of correlation between 



sound pressure spectrum level and maximum wave heights 

 for periods during which wave height at source was less 

 than 3 feet . . . 19 



