The mixing parameter k is proportional to l z in Equation (h) and can 

 be interpreted as the length of momentum transfer at the bottom of the 

 mixed layer, when the momentum transfer is reduced so much that the 

 restoring force of stability is sufficiently strong to prevent further 

 turbulent heat conduction across the interface. 



Solving (6) for h gives 



,B £ |n Hh } ir- 



Equation (7) can be used to compute h, if the wave parameters and the 

 corresponding value of k for existing stability in the thermocline are 

 known. 



Wave Parameters 



A total of 356 k values have been determined with known mean thermo- 

 cline depth and known wave parameters. These values were computed over a 

 large range of stabilities and wave spectra. The total wave spectrum 

 cannot be applied in Equation (7), owing to the complexities involved. 

 Certain wave heights and lengths are assigned as being characteristic of 

 given spectra. Significant wave height (HW3), the mean of the highest 

 one-third of the waves, was determined by the Pier son- Neumann- James method. 

 An amplitude equal to one-half of the significant wave height was then 

 used in Equation (6) for determination of k. Wave length was computed by 

 the relation X = 3.4l T max , where T max is the period of maximum energy of 

 the spectrum for a fully developed sea. When the sea was not fully developed, 

 significant height was determined accordingly, and the period of maximum 

 energy corresponding to that significant height for a fully developed sea 

 was used. When this period exceeded the maximum period possible for a 

 given non- fully developed sea, the latter period was applied. As a rule, 

 the wave parameters of a fully developed sea were used for determination 

 of k values; only a few determinations were made for a non- fully developed 

 sea, in which applicability of the method is not too certain. 



In use of Equation (7) for prediction of the thermocline depth, the 

 same characteristic elements of the sea spectrum (A = l/2 Hi/ 3 and 

 X= 3.4l TJ-gjjr) must be considered. If other representative elements of 

 the spectrum were used, such as mean height and mean period, a different 

 set of k values would apply. 



In summary, k values apply in Equation (7) in this study only with 

 significant wave heights and wave lengths computed with periods of maximum 

 energy of the spectra. 



Stability 



1 h P 



Stability, generally defined as E : r 3 — , is a function of tempera- 

 ture and salinity distribution, p/^I dS % A BT shows only the tempera- 

 ture distribution and does not obtain simultaneous salinity determination. 



25 



