Time-space distributions of the internal velocity were measured in Ariake Sound using Lagrangian-Acoustic Drogue for Intertidal environments (LAD-IT). The turbidity distributions were calculated using backscattering data of ADCP by solving the sonar equation. Time-space distributions of both the eddy viscosity and eddy diffusion coefficients were estimated using those of both the velocity and the turbidity. The estimated results indicated that the both coefficients changed temporally and spatially. The order of magnitude of the eddy viscosity was 10-3-10-2 and that of the eddy coefficient was 10-5-10-4. These orders were in good agreement with the conventional studies. The results indicate LAD-IT is adequate for estimating time-space distributions of eddy viscosity and eddy diffusion coefficients in the field.