Wave effects on coastal upwelling and water level

Abstract Traditional atmosphere, ocean and wave modelsare run independently of each other. This means that the energy and momentum fluxes do not fully account for the impact of the oceanic wave field at the air-sea interface. In this study, the Stokes driftimpact on mass and tracer advection, the Stokes- Coriolis forcing, and the sea-state-dependent momentum and energy fluxesare introduced into an ocean circulation model and tested for a domain covering the Baltic Sea and the North Sea. Sensitivity experiments are designed to investigate the influence on the simulation of storms and Baltic Sea upwelling. Inclusion of wave effects improves the model performance compared with the stand-alone circulation model in terms of sea level height, temperature and circulation. The direct sea-state-dependent momentum and turbulent kinetic energyfluxes prove to be of higher importance than the Stokes driftrelated effects investigated in this study (i.e., Stokes- Coriolis forcingand Stokes drift advectionon tracers and on mass). The latter affects the mass and tracer advectionbut largely balances the influence of the Stokes- Coriolis forcing. The upwellingfrequency changes by >10% along the Swedish coast when wave effects are included. In general, the strong (weak) upwellingprobability is reduced (increased) when adding the wave effects. From the results, we conclude that inclusion of wave effects can be important for regional, high-resolution ocean models even on short time scales, suggesting that they should be introduced in operational ocean circulation models. However, care should be taken when introducing the Stokes- Coriolis forcingas it should be balanced by the Stokes driftin mass and tracer advection.