628 



periods of wind forcing and the acceleration of the 

 mixing layer, but they are beyond the scope of this 

 paper. 



It seems likely that in the seasonal thermocline 

 short internal waves may break predominantly by 

 convective overturn whilst the longer are more 

 prone to K-H.I, but the balance of effects is not 

 known. The importance of non-linearities in 

 determining the condition of convective overturn 

 and the unknown structure of the density and veloc- 

 ity fields make the problem difficult to resolve 

 theoretically, and some effort is being directed 

 towards an observational, and hence empirical, 

 solution using small arrays of thermistors with 

 rapid response times, and sensitive CTDs. 



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