During the upwelling along the southern coast, the volume of water transported to the upper layer was larger than that off the northern coast, and the water mass was brought up from depths greater than 60 m (see Figures 7a, 7b and Figure 8). During the upwelling event along the northern coast, water was transported to the surface mainly from the depth range of selleck 21–41 m. There was a remarkable decrease from 3.7 × 108 m2 to 1.08 × 107 m2 in the amount of water transported to the surface from the 41–55 m depth range; hence, the maximum depth
influenced by the upwelling along the northern coast was about 55 m. In the case of the upwelling along the southern coast, such a depth interval with a rapid decrease of upwelled water volume was not detected; the volume of upwelled water decreased more or less uniformly with depth. The Antidiabetic Compound Library contribution from deeper layers during the upwelling with reduced wind stress (τ = 0.5 τ0) was lower for the upwelling events along both the northern and the southern coasts (see Figures 7b, 7d and Figure 8). The maximum depth influenced by the upwelling also fell to 45 m for the northern and 65 m for the
southern coast. In Figure 8 the shapes of the curves of transported water volume have been transformed into straight lines for both upwelling cases. Comparison of the changes in transported volumes during the upwelling along the northern coast with reduced wind stress from depths of 15–45 m with the results for the upwelling along the southern coast with reduced wind stress shows that transport from intermediate layers was reduced remarkably: the volume of water transported from 21 m depth was more than 50% smaller, but for the deepest layers, the decrease was 10 times larger. According to Lentz & Chapman (2004), the vertical position of the onshore
return flow that balances the offshore Ekman transport in an idealized case of stationary 2D upwelling is controlled by the Burger number S = αN/f, where α is the bottom slope, N is the buoyancy frequency and f is the Coriolis parameter. For ≪ 1 (weak stratification), bottom stress balances wind stress, and the onshore return flow is primarily in the bottom boundary layer. DOK2 For S ≈ 1 or more (strong stratification), the cross-shelf momentum flux divergence balances wind stress and the onshore return flow is in the interior. Despite the fact that real upwelling events in the Gulf of Finland are neither stationary nor two-dimensional, the finding by Lentz & Chapman (2004) may be used for the qualitative interpretation of the results obtained in this study. The estimates of the Burger number retrieved from the simulations were found to vary within the respective ranges of S = 0.3–1.2 and S = 0.2–0.9 for the upwellings along the southern and the northern coasts.