The behaviors of two limnetic river plumes discharging into the semi-enclosed western basin of Lake Erie during ice-free seasons

摘要

Given the significant ecological implications of coastal plumes, their dispersion and driving mechanisms have been extensively investigated, whereas existing knowledge about the limnetic ones remain unrevealed. Accordingly, this study investigated the behaviors of the Detroit (DRP) and Maumee (MRP) River sediment plumes in the semi-enclosed western basin of Lake Erie on multiple temporal scales. Results demonstrated that the two plumes' dispersions were constrained by the basin's coastlines beyond the advections induced by Ekman currents. The north and west wind forced MRP traveled downstream, while those under the south and east wind propagated upstream. The inter-annual and seasonal variability of MRP sizes are mainly impacted by its river flux, with moderate contributions of zonal wind and the Detroit River flux, resulting in significantly larger spring patches and indicating the potential interactions between the two plumes. On the other hand, DRP paced upstream under the west wind, traveled downstream under the north and east wind, and the south wind induced advection confined it at its river mouth. Its sizes varied with wind forcing and were significantly influenced by wind directions. They had limited inter-annual variations but with prominent seasonality, which featured for small summer surface patches resulting from its negative buoyancy. Overall, this study demonstrated the behavior of two dynamically distinctive limnetic plumes bounded in a semi-enclosed basin, which could further our understanding of plume dynamics in lakes and enclosed environments.