A MODEL OF A DRIFTING ICE COVER

Some theoretical ideas are developed concerning the dynamics of a drif ting ice cover modelled by a four-phase two-dimensional continuous med ium with elastic-plastic theology under bulk and shearing deformations , including processes of hummocking and the formation of fractures [1] . Phase transition conditions are formulated in closed form, depending in general on eight functions that characterize the theological prope rties of the sheet. New exact solutions are developed for the model eq uations, describing a diverging ice cover drifting in the field of an ocean eddy, the interaction of a diverging ice cover with surface wave s, the plastic flow of a close pack ice cover under the influence of a localized sea current, and the collision of a close pack ice massif w ith a rigid, wedge-shaped wall.