A ONE-DIMENSIONAL ICE THERMODYNAMICS MODEL FOR THE LAURENTIAN GREAT-LAKES

Great Lakes hydrologic research requires the use of continuous-simulat ion daily ice cover models over long time periods in the absence of fi eld observations. They must be physically based, rather than statistic ally based, for use under conditions different than those under which they were derived. But they also must match existing conditions for wh ich data exist. A review discloses that existing ice dynamics models d o not meet all of these criteria; a new one that does is based here on a prismatic ice pack heat balance, ice growth and temperature constra ints, and thermodynamic flux terms from companion water heat balance a nd storage equations. The prismatic ice model is a good first step to understanding complex geometries and is supportable through the use of lake-averaged energy fluxes. The ice model is integrated into an exis ting lake thermodynamics and one-dimensional heat storage model, and t he resulting combination is calibrated for Laurentian Great Lakes appl ications. Simulation experiments are used to analyze the model's stren gths and limitations and to explore its relevance. Comparisons between model output and existing data allow consideration of the ice climato logy of the Great Lakes; the climatology description is extended throu gh use of the new model. Promising potential model extensions include spatial extension, additional parameterizations for wind-ice movement, snow, and albedo, and inclusions of remotely sensed data.