The Cooling Box Problem: Lab and Field Measurements

Jason Olsthoorn1, Edmund W Tedford2 and Gregory A Lawrence2, (1)University of British Columbia, Civil Engineering, Vancouver, BC, Canada, (2)University of British Columbia, Department of Civil Engineering, Vancouver, BC, Canada
Abstract:

The world's lakes are getting warmer and recent global studies have shown that seasonally ice covered lakes are warming the quickest. As ice covered lakes have historically been largely ignored in the literature, there has been a significant recent push in the limnological community to study the various physical and ecological processes occurring before, during and after ice formation. In particular, radiatively driven convection has received a lot attention in recent citations.

In this presentation, we will discuss decaying thermal convection prior to ice formation. We study a warm, fresh body of water that is cooled from above. The air temperature above the water surface is below the freezing temperature of water such that the surface of the water will eventually freeze. We perform laboratory experiments to study this physical setup and we make direct comparison with field measurements. We compare these results with the theoretically and numerically predicted scalings of the surface heat flux based upon the Rayleigh number and a temperature difference parameter. These results may enable us to better predict the surface heat fluxes out of a lake from standard field measurements.