Sea ice rheologies that employ teardrop and parabolic lens plastic yield curves have been developed. These rheologies obey the normal flow rule when ice fails, and allow varying amount of biaxial tensile stress in line with laboratory observations of ice mechanical property. In order to examine the effects of plastic rheology, the teardrop and lens rheologies, together with some existing plastic rheologies, have been implemented in a thickness and enthalpy distribution sea ice model for the Arctic Ocean.

A series of model integrations indicate that rheologies that follow the normal flow rule have shear stress distributions with two peaks, one at the zero shear stress and the second between 16,000-22,000 N/m. A fatter yield curve or one with biaxial tensile stress tends to increase the frequency of large shear stresses. An increased frequency of large shear stresses tends to enhance ice ridging in the Arctic interior and reduce ice ridging in the coastal areas, which affects arctic spatial ice mass distribution and the total ice budget. The results also indicate that plastic rheology, which affects the solution of ice motion, deformation, and thickness, has a significant impact on the computation of surface energy exchanges.