Abstract
Our observation of a dye diffusion (in which uranin was used) was carried out at Tokyo Bay on October 13, 1968. This paper deals with the state of a dye diffusion as revealed by the measurement of the photo density of a dye patch with a photodensitometer.
Our previous study of dye diffusion in the ocean (carried out in 1965 and 1966) was based on two widely held assumptions: one-that dye density is inverlsey proportional to the area of the dye patch; two-that dye density is homogeneous in a dye patch. In our most recent study we found that the density of a dye patch could be determined by measuring the density of the distribution with a photodensitometer. Further, we found that the relation between photo density and dye density corresponded to the equation logY (mV) =alogc+b. Using this equation, we estimated the dye density from the photo density of the dye patch. Then, we calculated the coefficient of dye diffusion by using formula (3) .
In another case, we assumed that the density of a dye patch was homogeneous. In this case, we estimated the coefficient of the dye patch by using formulas (4) and (5) .
In comparing the results of these two coefficients we found that the 1st coefficientKXequaled 104-106andKYequaled 103-104. (These figures are rather large.) In the second coefficientKXequaled 103-105and KYequaled 101-103.
Theoretically, the former method is superior to the latter; but the data obtained from the former was not quite satisfactory because of the fact that it was based on our assumptions.
Further studies will have to be made before these assumptions can be proven to be absolutely correct. When these studies are made, care will have to be taken to insure that the scale of turbulence is taken into consideration.
