Coupled Ice-Ocean Dynamics in the Marginal Ice Zones: Upwelling/Downwelling and Eddy Generation

摘要

A two-dimensional coupled ice-ocean model is used for this study of meoscale processes. The ice model is coupled to the reduced gravity ocean model through interfacial stress. The parameters of the ocean model were chosen so that the dynamics would be nonlinear. The model was tested by studying the dynamics of upwelling. Winds parallel to the ice edge with the ice on the right produce upwilling because the air-ice momentum flux is much greater than air-ocean momentum flux; thus the Ekman transport is greater under the ice than in the open water. The stability of the upwelling and downwelling jets is discussed. The downwelling jet is found to be far more unstable than the upwelling jet because the upwelling jet is stabilized by the divergence. A constant wind field exerted on a varying ice cover will generate vorticity leading to enhanced upwelling/downwelling regions, i.e., wind-forced vortices. Steepening and strengthening of vortices are provided by the nonlinear terms. When forcing is time varying, the advection terms will also redistribute the vorticity, Wind reversals will separate the vortices from the ice edge so that the upwelling enhancements are pushed to the open ocean and the downwelling enhancements are pushed underneath the ice. Keywords: Ice-edge upwelling/downwelling, Ice edge eddies, Two-dimensional ice-ocean model, Ice-ocean/Air-ice interfacial stresses, Ekman transport. (Reprints)