Observations of coastal and open water internal wave generation in Lake Superior

Erica Green1, Samuel Maurice Kelly1, Jonathan D Nash2, Jay A Austin3 and Andrew J. Lucas4, (1)University of Minnesota Duluth, Duluth, MN, United States, (2)Oregon State University, Corvallis, OR, United States, (3)Univ Minnesota Duluth, Duluth, MN, United States, (4)University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States
During the summer, Lake Superior (mean depth 147m) is dominated by near-inertial motions and internal waves with negligible tides, making it an ideal “laboratory” to study the generation of wind-driven near-inertial waves. In the summer of 2017, twenty moorings distributed across the western arm of Lake Superior collected measurements of temperature, velocity, and turbulence. These observations allow us to quantify mechanical energy pathways from wind work to internal wave generation, radiation, and dissipation. We show that near-inertial wave generation differs near the coast and in the open lake, because the former is impacted by coastal upwelling and the latter is impacted by open-lake wind and meanflow variability.