Author(s): Margaret A. Knuth; Hayley H. Shen
Linked Author(s): Margaret Knuth
Keywords: Sea ice; Pancake ice; Modeling; Discrete element
Abstract: Existing sea ice models do not predict ice edge phenomena observed in satellite images. It is likely that important ice processes near the edge are still missing in these models. In the presence of a wave field, which is often present at the ice edge, ice growth is not entirely controlled by thermodynamics. The thickness and morphology of an ice cover becomes a competition between the vertical thickening of floes due to rafting and the lateral growth due to the freezing of neighboring floes. This study focuses on creating a computational tool to study the development of the sea ice field by composite growth. Composite growth is attained by floe collisions produced from wave induced ice drift. With adequate contact time the neighboring floes can freeze together thus creating a larger conglomerate. Wave parameters determine the drift, and therefore the contact that occurs, along with the amount of stress the floes are under which can break the frozen bond. Thus, the final size of these floes, or the number of pancakes frozen together as one floe, is dependent on the wave height and frequency. Computer simulations are done with a threedimensional discrete element model that simulates the movement of disc-shaped floes in a wave field. A total of twenty cases have been simulated. It is shown that the maximum size of the frozen composite pancakes qualitatively agree with previously reported theoretical predictions. To capture the important physical processes in freezing and fracturing of composite floe, several important improvements are still required.
Year: 2006