On the boundary-layer flow over a Canadian Archipelago polynya

A numerical model is presented for predicting boundary-layer parameters for flow over a polynya, i.e., an isolated lead of open water that recurs annually at the same geographical location during Arctic winters. As the flow encounters a polynya, it experiences a sudden change from a cold, dry, rough, snow-covered ice surface to a warmer, wetter, and smoother open water surface. The present model includes both the heat balance equation and the vapor conservation equation in addition to the usual mass continuity equation, x-momentum equation, and the turbulent energy equation. In addition, the buoyancy term is added to the energy equation to account for the buoyancy force introduced by the underlying warmer surface. To close the system, the present model uses the Glushko-type mixing length relationship. During the numerical calculations, a fully implicit finite-difference method was used, and stable numerical solutions were obtained for a fetch over 1 km. Comparison of model results with measured results over a polynya in the Canadian Archipelago show good agreement.