Tidal Turbulence and Eddy-Viscosity in Coastal Waters at Northeastern Brazil

Abstract

Abstract Vertical distribution of Turbulent Kinetic Energy (TKE) at coastal NE-Brazilian waters was evaluated using a combination of field data and numerical modelling. Microestructure temperature profiles obtained with a SCAMP probe were used to estimate the rate of TKE dissipation at coastal waters off Suape Harbour. SCAMP measurements and field cinematic information were then used as input data to a turbulence model and numerical results used to obtain simple eddy-viscosity formulations as a function of low-order parameters associated to measured characteristics of velocity profiles. Stronger TKE dissipation rates at Suape waters showed to be associated to surface and bottom boundary layers during spring tides, with values ranging between 5 × 10−7 m2s−3 ≤ e ≤ 3 × 10−6 m2s−3. Less accentuated dissipation rates were found at the interior regions of the flow, with 5 × 10−8 m2s−3 ≤ e ≤ 2 × 10−7 m2s−3. Numerical results indicated that energy balances immediately near boundaries are mainly driven by an equil...