The objectives of this paper were (1) to simulate flow velocity and surface wave fields in the Suur Strait and to validate these with in situ observations; (2) using simulation results, to estimate the proportion of surface waves in the

flow field and water exchange through the Suur Strait; and (3) using observation data and model simulations, to estimate wave-induced and current-induced shear velocities. This paper is structured as follows. In section 2, the field data, circulation model and wave model are briefly described, and the wave and current shear velocities are calculated. In section 3, the model results are presented, discussed and compared with the measurements. The conclusions are drawn in section 4. Current velocity and wave measurements CDK inhibitor in the Suur Strait were performed in November–December 2008. A buoy station equipped with a Sensordata current meter SD-6000 and a pressure sensor was deployed on 13 November near Virtsu (58°34.95′N; 23°29.30′E, Figure 1c). The water depth at the location of the buoy station was 9 m. The current meter was at a depth of 3.5 m and the wave gauge at 2.5 m. The current speed and direction recording interval was 5 min, that of the wave gauge 0.25 s. Current measurements lasted until 4 December and wave measurements AZD6244 until 6 December. The method for reconstructing surface elevation spectra from sub-surface pressure recordings is described in detail by

Alari et al. (2008). Wind speed and direction were recorded with the Väisälä Weather Transmitter WXT520

installed at a height of 30 m at the Kessulaid weather station (Figure 1c). It recorded wind data at 5 min intervals from 21 November to 13 December. We used a height correction factor of 0.91 to reduce the recorded wind speed to the reference height of 10 m (Launiainen & Laurila 1984). We used a two-dimensional circulation model based on the hydrodynamic equations for a shallow sea. The model had been applied earlier to different regions of the Estonian coastal sea (Sipelgas et al. 2006). The model consists of vertically integrated motion equations equation(1) ∂u∂t+u∂u∂x+v∂u∂y−fv=−g∂η∂x+Fwxh−Fbxh+Fwavexh+Gx,∂v∂t+u∂v∂x+v∂v∂y+fu=−g∂η∂y+Fwyh−Fbyh+Fwaveyh+Gy Sulfite dehydrogenase and a continuity equation equation(2) ∂η∂t+∂uh∂x+∂vh∂y=0, where (u, v) are the vertically averaged velocities in the water column in the Cartesian coordinates, (Fxw, Fyw) are the kinematic wind stresses, (Fxb, Fyb) are the bottom friction stresses, (Fxwave, Fywave) are the wave-induced forces, (Gx, Gy) are the horizontal turbulent viscosities in the (x, y) directions, f is the Coriolis parameter, g is the acceleration due to gravity, η is the sea surface elevation (deviation from the equilibrium depth) and h(x, y) is the depth. In order to take into account the wave-induced currents, a wave-induced force per unit surface area is added to the kinematic wind stress in both the x and the y directions.