FIGURE 23 SHORT PERIOD FLUCTUATIONS OF THE THERMOCLINE AT 

 WEATHER SHIP ALFA, 6™,,33°W., I500-I700Z, 22 

 SEPTEMBER 1945. 



There Is little doubt that short period oscillations as 

 described above is one of the main factors that cause discrepan- 

 cies between theoretically computed and actually observed sonar 

 conditions. However, the limitations of the available data have 

 made it impossible to approach this problem in conjunction with 

 the longer period waves. It is hoped that in the future arrange- 

 ments can be made for such data to be collected and the problem 

 Investigated, 



e. Random variations due to mixing - Since the mechanisms 

 that cause mixing in the ocean are mainly meteorological in 

 nature, this problem has been discussed in the earlier portion 

 of this report. It was concluded that there were two main proc- 

 esses that affect the depth of the thermocline: convectional 

 mixing due to instability, and turbulent mixing due to wind and 

 sea, V/hen the random effects of these two processes are superim- 



47 



