A two-dimensional thermal-ice model for river channels

In this study the dynamic river ice model DynaRICE was generalized to include all thermal-ice processes. These processes include: heat flux on the water/air and ice/air interface and associated water temperature changes; static border ice formation; skim ice run; dynamic border ice development; supercooling and frazil production; mass exchange between suspended ice and surface ice; anchor ice evolution; thermal growth and decay of ice floes and ice cover; undercover transport and ice cover breakup.; The depth-averaged water temperature in the river was simulated with a finite-element solution for the transport of thermal energy. This solution was then used as a basis for simulating several freeze-up ice processes. The skim ice formation is determined by the water surface temperature calculated from the depth-averaged water temperature with an empirical relationship. The frazil ice concentration and supercooling is calculated by considering the heat exchange between the river water and suspended frazil ice crystals. The suspended ice concentration is modified by exchanges between the suspended ice over the flow depth and the surface and anchor ice. The surface ice transport and accumulation is modeled by ice dynamics as did in the DynaRICE model. The thermal growth and decay of ice thickness is simulated by heat conduction across the ice cover of floes. The undercover ice transport is modeled using an ice transport theory. Both anchor ice evolution and ice breakup processes are the least understood processes in river ice. The model uses a simple formulation for anchor ice evolution and uses an empirical approach to simulate ice cover breakup.