Sea-ice arching and multiple flow states of Arctic pack ice

Abstract

Flow of ice through narrow channels is significantly affected by the amount of shear strength in plastic rheologies used in sea-ice models as well as in reality. When thermodynamics is added to this problem, the capability of multiple flow states for the same forcing through narrow passages arises. To understand this problem and examine the potential for seasonal stoppage of flow through passages constraining the Arctic basin outflow, the effect of sea-ice rheology on idealized flow through narrow passages is first analyzed. This ideal analysis is then combined with thermodynamic effects and fluctuating wind fields in an Arctic basin dynamic-thermodynamic sea-ice model with multiple outlet passages. The results demonstrate that the capability for multiple flow states existing through passages depends on the initial conditions and general 'climate' state, and yield insight into the general parameter range over which the seasonal stoppage might irreversibly shift to an unconstrained outflow regime.