Sea-Ice Deformations at the Submesoscale and Below During the Melting Season

Abstract

Many sea-ice models formulate sea-ice rheology by a viscous-plastic approach with an elliptical yield curve and a normal flow rule. However, it remains uncertain whether this formulation is suitable for finer-resolution climate models in the warming Arctic. We analyze sea-ice deformation using half-hourly Global Positioning System (GPS) data initially spaced approximately 100 m to 10 km apart from March–July 2020 and 2022 in the Beaufort Gyre. Our findings show the prevalence of shear-dominated deformation and the greater capacity for persistence in the convergence-dominated deformation compared to divergence-dominated deformation. The former supports the sine-lens yield curve, while the latter supports the teardrop yield curve. Our results examine the validity of the elliptical yield curve during sea-ice breakup and advocate the need for a combination of sine-lens and teardrop yield curves from data-supported arguments.