Presented by: Jay Austin from the Large Lakes Observatory Department of Physics University of Minnesota, Duluth
Friday, Sept. 21
325 Hagen Hall
Near Inertial oscillations, which are due to the propagation of Poincare’ waves (rotationally modified gravity waves) dominate the kinetic energy field in Lake Superior during stratified periods, resulting in near-surface velocities of up to 0.4m/s and velocities near the bottom in excess of 0.1m/s. These waves propagate along the density interface between warm surface waters and cooler bottom waters. Data from several sites suggest that the direction of propagation of the wave field appears to rotate counter-clockwise around the lake with a period of approximately one month. In this talk, we will discuss the nature of these waves, the role that density stratification plays, the equipment we use to measure velocity and temperature structure in lakes, and some of the potential ecological implications of the wave field.