Evaluation Factors of Horizontal Turbulent Exchange in the White Sea According to Flow Measurement

Zhegulin G. V., Zimin A. V.

The coefficients of horizontal turbulent viscosity and their variability with the depth depending on the averaging period of flow rates are calculated on the basis of an increased flow velocity measurement data performed in the heavy areas of the White Sea. The technique of sliding averaging was used to eliminate the orderly movement in the velocity field, and the selection of local effects was carried out on the basis of wavelet analysis. The results indicated the possibility of release the time interval scale inflow of energy from the energy-ordered motions in the White Sea (fluctuations with the tidal frequencies M2, M4 and M6, the mechanism of the regular adjustment of currents, bottom friction), and unstable external sources (baroclinic currents, the disintegration of the internal tide, short-period internal waves). It was found that the anisotropy increases with the averaging period. Under certain extent of smoothing the flow velocity, mainly for the central regions of the flow field, the field of pulsations of a horizontal vector of speed is isotropic. Taking into account the exclusion of influence of external sources of energy in the flow structure and the surface wind and wave processes the values of eddy viscosity coefficients along the flow was 102—105 sm2⁄s, and in a direction normal to the flow the exchange ratio was 1—3 times smaller.

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