Evaluation of the coefficients of horizontal exchange in the Black Sea according to the data of drifter experiments

We generalize the method used for the evaluation of the coefficients of horizontal diffusion of Brownian particles to the nonstationary case, as applied to the drifter experiments. The limits of applicability of the proposed procedure are determined. The coefficients of horizontal exchange are computed with an aim to compare them with the estimates obtained earlier by using the generalized Taylor theory. The mutual agreement of these estimates is demonstrated. It is shown that the difference between the values of the zonal (0.19⋅10⁴ m²/sec) and meridional (0.11⋅10⁴ m²/sec) coefficients of exchange in the Black Sea cannot be explained by the effect of increase in the longitudinal component of pulsations of the velocity as a result of its transverse shear relative to the mean current. A conclusion is made that the processes of horizontal exchange in the Black Sea are geographically anisotropic.