Reliable prediction of hypoxic events in the coastal ocean and lakes depends to a large degree on the ability of hydrodynamic models to accurately simulate nearshore circulation and thermal structure. With focus on the hypoxia-prone south shore of Lake Erie, temperature and currents were measured in the central basin in 2017-2019. Major upwelling events along the south shore were identified and linked with occurrence of strong, sustained wind from the northeast (NE). A three-dimensional FVCOM-based hydrodynamic model was able to predict upwelling events along the south shore reasonably well but the surface mixed layer and thermocline depth were shallower than in observations. It was found that basin-scale wind stress curl (WSC) transformed canonic two-gyre circulation in the uniform NE wind case into a single gyre circulation causing both alongshore and cross-shore current reversal that modified coastal upwelling/downwelling. Observational evidence of Kelvin waves on the south shore was found for the first time. Kelvin wave speed in the model was underestimated. Model runs with enhanced vertical mixing improved predictions of mixed layer and thermocline depth and near-bottom dissolved oxygen but also caused additional diffusion of thermocline.
