[en] When taking small-scale structure field measurements in the upper stratified layers the probe-turbulimeter with high sampling frequency is used. By the spectra of temperature fluctuations and velocity we are evaluated by virtue of the previously developed theory the characteristic scales of turbulent patches formed due to the internal waves breaking. Then the vertical turbulent diffusion coefficient dependence on buoyancy frequency for the specified layers is determined. It is shown that the spatial distribution of coefficient depends on the bottom topography; its maximum values are concentrated in the interface area of the shelf and continental slope, due to intensification of shear instability and internal waves breaking in this region. (paper)