Mechanical thickening and thermodynamic growth processes of ice coves in a wave field.

摘要

In ice formation stage, with the influence of waves, ice frazil crystals coagulate and consolidate into small circular discs called pancake ice. Pancakes grow by accumulating ice crystals from the surrounding water and from bonding with neighboring discs. As the penetrating waves gradually lose energy the pancakes freeze together to form a consolidated ice cover.; In this thesis, a theory that allows us to predict the thickness of the consolidated ice cover is proposed. This equilibrium thickness from the theory is proportional to the square of the wave amplitude, square of the pancake floe diameter and inversely proportional to the cube of the wavelength. The results of the theory are compared with laboratory experiments and with numerically simulated processes. Both the laboratory and the computer simulation results compare favorably with the theory.; The thermodynamic ice growth rate up to the pancake ice formation stage is also investigated in this thesis and found to be enhanced with the presence of waves.; Finally, the effects of the equilibrium thickness on the area] development of ice cover are tested using a coupled ocean-ice model. Results show that larger equilibrium thickness generates greater and more rapid development of ice cover.