IMPACT OF ICE QUALITY ON RADIATIVELY DRIVEN CONVECTION DURING SEASONAL ICE COVER ON LAKES

Lakes that experience seasonal ice cover are not quiescent during ice-on due to the buoyancy driven flows within the water column. As winter progresses into spring, an increase of solar radiation through the ice generates currents that can transport nutrients into the water column triggering early growth of phytoplankton which can lead to blooms during or soon after ice cover. Prior to freezing, the lake conditions dictate the quality of the ice, for example, calm conditions will lead to highly transparent black ice, whereas variable conditions will lead to opaque white ice. Further, as the planet undergoes climate change, warmer average temperatures are resulting in thinner ice cover, thus, it is important to investigate how this change in ice quality impacts lake circulation which further dictates other biophysical processes. To tackle this, solar radiation is incorporated to the incompressible Navier-Stokes equations via the Beer-Lambert law which are then numerically solved on an initially thermally stratified domain. A fixed ice boundary with no melting is assumed in order to investigate the impact of ice quality as light starts to consistently penetrate the water column as in spring. It is found that ice quality impacts the flow in a meaningful way, for example, black ice reduces the duration of time for the onset of convection and enhances mixing compared to white ice as more light is allowed to propagate and transfer thermal energy into the water column.

Primary Presenter: Benjamin Smith, University Wisconsin-Madison (bjsmith28@wisc.edu)

Authors:

Benjamin Smith, University of Wisconsin-Madison  (bjsmith28@wisc.edu)

Till Wagner, University of Wisconsin-Madison  (till.wagner@wisc.edu)

Nimish Pujara, University of Wisconsin-Madison  (npujara@wisc.edu)

Timothy Bertram, University of Wisconsin-Madison  (tbertram@chem.wisc.edu)

Hilary Dugan, University of Wisconsin-Madison  (hdugan@wisc.edu)

Grace Wilkinson, University of Wisconsin-Madison  (gwilkinson@wisc.edu)

Lucas Zoet, University of Wisconsin-Madison  (lzoet@wisc.edu)

Jennifer Franck, University of Wisconsin-Madison  (jafranck@wisc.edu)