CONTENTS 



LIST OF SYMBOLS . . . page 5 



INTRODUCTION ... 7 



ENERGY TRANSFER FROM SURFACE WAVES TO INTERNAL WAVES BY 

 RESONANCE ... 9 



EQUATIONS AND BOUNDARY CONDITIONS ... 70 



THE PERTURBATION EQUATIONS ■ ■ ■ U 



THE EQUATION FOR w U, z, t) . . . 13 



THE PRIMARY WAVE FIELD AND THE FORCES fi and (2 ■ ■ ■ 15 



THE SECONDARY WAVE FIELD IN THE RESONANCE CASE ... 77 



F± (z) G- (0) and A- IN CASE OF AN EXPONENTIALLY 



mn ' mn mnr 



STRATIFIED SEA ... 79 



THE SECONDARY RESONANCE WAVE FIELD DLIE TO SWELL IN CASE OF 

 AN EXPONENTIALLY STRATIFIED SEA . . . 23 



MEASUREMENTS ON SWELL AND INTERNAL WAVES ■ ■ ■ 24 



CONCLUSIONS ■ . .26 



RECOMMENDATIONS ... 27 



REFERENCES . ■ . 27 



ILLUSTRATIONS 



Temperature recorded by thermistors 3 to 21 at the NEL Tower (4 October 

 1966, 1900-2000) . . . page 8 



Amplitude (cm) of internal waves due to modulated swell after an interac- 

 tion time of 103 seconds (16.6 minutes) as a function of the angle 

 between the two primary waves ... 23 



Swell spectra of wave height sensors 1 and 2 at positions near the NEL 

 Tower, and phase difference between both records (4 October 1966, 

 1230-1330, sampling rate 1 second); the arrow indicates the 95-percent 

 confidence limit ... 25 



Histograms of periods of swell modulations (left) and of internal waves 

 (right) at the NEL Tower . . . 26 



REVERSE SIDE BLANK 



