Seminar: Jay Austin – UMN Duluth

UNC-CH’s Department of Marine Sciences is proud to host a guest seminar by Jay Austin. This event is scheduled for Wednesday, March 3rd, at 12:30 pm. This seminar is remote only and will be broadcast live online via Zoom (Meeting ID: 934-0604-8353).

Presenter Affiliation: Professor, Large Lakes Observatory / Department of Physics and Astronomy, The University of Minnesota at Duluth.

Title: Radiatively Driven Convection in a deep freshwater lake

Abstract: Radiatively Driven Convection (RDC) occurs in cold freshwater lakes in the springtime when solar radiation heats surface waters below the temperature of maximum density. Early studies using moored platforms and an autonomous glider revealed aspects of the structure of convective cells, with scales of variability on the order of 10’s of meters, temperature anomalies on the order of 0.1K, and vertical velocities on the order of 1-2cm/s. Convection is capable of completely mixing the water column (180m depth) on the order of hours. A subsequent deployment included a large two-dimensional (lateral and vertical) 150m x 150m array of thermistors with horizontal resolution of 10m, as well as an ADCP mooring and a meteorology buoy capable of estimating heat and momentum fluxes. The combination of temperature and current data allows us to study convective features with centimeter resolution, demonstrating that the boundary between ambient water and recently warmed downwelling water to be very sharp- on the order of 10’s of cm. Finally, using backscatter intensity from the ADCP, we should that convection has a first-order impact on the vertical migration behavior of zooplankton.