Observations of Stress and Strain at Floe Scale in Sea Ice

Abstract:

Sea ice drifts and deforms under forces imparted by winds, currents, and contact with land, all transferred through the ice over long distances by ever-evolving stress pathways through the ice pack. These forces and the manner in which they are transmitted through the ice govern the ice motion, internal stress state, and fracture - collectively driving ice dynamics. As part of the Sea Ice Dynamics Experiment (SIDEx), we are observing, for the first time, stress-strain fields in floe-scale sea ice domains (~0.1-4km2). We seek to use these data to understand how heterogeneity in ice strength and ice floe geometries generate local concentrations of far-field stress, resulting in fracture and deformation. Four field programs have been conducted to date, two at U.S. Navy Ice camps in the Beaufort Sea, one in landfast ice near Utqiagvik AK, and one in the Central Arctic as part of the MOSAiC international drift experiment. Here we give an overview of the observations of stress data collected with vibrating wire gages and strain observations collected over km-scale distances with a laser strain observing system. We discuss the nature of stress propagation elucidated by these observations and how this informs our experimental design for SIDEx 2021.