1 1 \ r 



"1 1 \ r 



50- 



45- 



^40- 



< 



> 



^35- 



O 



O30- 



§25 



z 



20- 

 15 



WAVE PERIOD (MINUTES) 



Figure 18. Composite frequency distribution of internal wave periods 

 over 2 seconds (light and dark shading) and internal wave periods with 

 associated internal waves (dark shading) for all data. 



Wave Periods and Slicks 



Slicks were generally associated with the longer-period waves, but were absent 

 from the longest-period wave. Slicks are more related to wave height than to 

 wave period for the depths of thermoclines and water observed. 



From observations of wave speed, an estimate of wavelength can be made. It 

 was found by use of range markers that the speed of definite slicks was 0.31 knot. 

 Since the internal wave travels at the same rate as the slick, the same speed ap- 

 plies to internal waves. A wave of average period 7.6 minutes would be 236 feet 

 long. 



24 



