SECT. 5] 



IKTERNAL WAVES 



737 



Fig. 7. Depth of 64°F isotherm measured with isotherm follower from 1500 h, 23 September, 

 to 1500 h, 24 September, 1959, off Mission Beach, California. 



the lower ones were probably only random fluctuations. It was found that 50% 

 of the internal waves were higher than 5.6 ft. 



b. Wave period 



The frequency distribution for the duration of 1061 internal waves is shown 

 in Fig. 9. Waves with periods of less than 2 min were excluded. Fifty per cent 

 of all waves longer than 2 min had periods greater than 7.3 min. 



WAVE 



HEIGHT 



(FT) 



WAVE 



PERIOD 



(MIN) 



[■: :-:t>:-:-:-:-{:i:':-:":-:-:-:-L-:-:-::-:-:-i 



4 8 12 16 20 24 



Fig. 8. Composite frequency distribution 

 of internal wave heights over 2 ft (for 

 1958 and 1959 combined). 



'0 4 8 12 16 20 24 



Fig. 9. Composite frequency distribution 

 of internal wave periods over 2 min 

 for all data. 



