If the dye patch is described by a mean radius R, the surface 

 area can be expressed as: 



Surface area <X R^ 

 and from observations: 



Surface area OC T 

 where T is time elapsed after dye release. 

 Therefore, R a T°*5 



The concentration data can be expressed as: 



Concentration cc — ; — - — CC — o 



volume of dye RJ 



and from observation: 



Concentration OC T"^*5 

 Therefore , R CC T 2 * 5 '3 • ° 



or: R GC T ' 8 



The two results are: 



From area measurements: R CC T^*5 



From concentration measurements: R OC T^* 



The more rapid increase of radius by the concentration measure- 

 ments implies that the dye is sinking. 



In summary, the measurements indicated turbulent mixing processes; 

 presence of near- surface jets; that the dye first followed the wind, 

 then the current; that the dye was sinking; and that motion in the sur- 

 face waters approximated an Ekman spiral. 



Conclusions 



Certain characteristics of the water flow can be estimated from 

 aerial photographs of dye patches. These include nature of the flow 

 (turbulent or laminar), the mean flow (if a reference point is avail- 

 able), and the amount of near-surface shear. If surface concentration 

 measurements are available, the vertical motion might be estimated. 

 The photographs indicated that Rhodamine-B dye is best photographed 

 w;Lth a high-speed black-and-white film with a filter centered at O.56O 

 micron. 



27 



