D=D + A,sin ^ + B,cos2ff^ + A2sin^ 



+ t t (^'^ 



In this expression D represents the seasonal effect, and 

 may be taken as the mean depth of the thermocline for a particu- 

 lar month. The 2nd through 6th terms represent periodic effects 

 due to the lunar, diurnal, and semidiurnal waves. In the last 

 term, W is some function which represents the mixm;; processes 

 that take place. It might be a complicated function of wind and 

 sea, and only experiments will determine its exact nature. The 

 contribution to the amplitude of the oscillations of the thermo- 

 cline made by the lunar wave would be represented by-JA.^+B,^ 

 and the phase change from the lunar at the thermocline depth is 

 given by tan v^ The same relationships obtain for the 



semidiurnal and diurnal waves. The normal procedure in such a 

 study would be to evaluate from known data the constants Aj., Ao, 

 B^j 62* etc., and to assume that these constants hold with time 

 for that particular place. Assuming; this to be so, one could, 

 therefore, knowing D and the other factors, evaluate D for a 

 particular time. 



There is no evidence that either the amplitudes or phases 

 of the constituents waves are conservative with time. On the 

 contrary, there is evidence to support the I'act that both the 

 amplitudes -and phases vary with time and also with depth at one 

 particular time. Another difficulty lies in the nature of the 

 function if the wind uhich must be used to evaluate turbulent 



49 



