Sahool&y 



I. INTRODUCTION 



The oceans are dominated by several turbulent processes. 

 For each turbulent situation there are "eddy" diffusivitles of tem- 

 perature and salinity that are much larger than the molecular 

 diffusivitles. In spite of the difficulties in measuring eddy diffusi- 

 vitles at sea, there is considerable, though incomplete, literature 

 on the subject [ Neumann and Pierson, 1966] . Since turbulent ocean 

 processes are inherently uncontrollable, several exploratory labora- 

 tory experiments were conducted in late 1964 and early 1965. This 

 paper is the first publication of the results of these preliminary 

 experiments . 



II. APPARATUS. 



Figure 1 shows the test cell where the experiments were 

 conducted. It has transparent plastic walls and is 30 cm long, 

 9 cm high, and 2. 5 cm thick. The bottom 4 cm was filled with either 

 room temperature distilled water or a 0.25% solution of sodium 

 chloride, depending whether thermal or salinity diffusion was to be 

 studied. The molecular thermal diffuslvity of pure water at at- 

 mospheric pressure and 20^0 is 0.00143 cm^sec (4% less than sea 

 water). The molecular diffuslvity of an aqueous NaCl solution is 

 0.0000141 cmVsec (9% less than sea water) according to Hill [ 1962] . 

 Convenient distilled water and NaCl solutions were used instead of 

 sea water because of these relatively small differences. 



Fig. 1. Experimental cell. Temperature difference sensor near 



center. Salinity difference sensors at right. L shaped wire 

 at left produces turbulence on demand. 



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