Effective Elastic Parameters for In Situ, Drifting Sea Ice Under Natural Forcing Conditions at Kilometer Scales

Stress–strain relationships are fundamental to understanding deformation mechanics in any material. In sea ice, stress–strain relationships are typically observed by measuring the strain resulting from known stress in samples wholly or partially isolated from the surrounding ice. Such observations show sea ice behaves elastically at short timescales, and the effective parameters describing this elastic behavior vary with temperature, salinity, and strain rate. However, these experiments often employ larger strain rates than are typical for intact, in situ ice, are labor intensive, and are typically limited to meter scale. Here we utilize a novel synthesis of existing observation techniques to quantify the effective elastic modulus and Poisson's ratio of a km‐scale area of heterogeneous, drifting sea ice surrounding the Sea Ice Dynamics Experiment (SIDEx) drifting ice camp in the Beaufort Sea. In‐ice point measurements of two‐dimensional horizontal stress from an array of 31 vibrating wire stress gauges (VWSG), distributed over a ∼1.5 km radius area, allow us to observe natural forcing conditions. A ground‐based interferometric radar provides contemporaneous one‐dimensional surface strain measurements collocated with stress within 22.5 m resolution cells. We find an effective elastic modulus of 2.4 0.6 GPa and effective Poisson's ratio of 0.5 0.2 describe the heterogeneous, mixed multi‐ and first‐year ice within the area of the VWSG array. These values are broadly consistent with prior laboratory and field experiments while offering a novel point of reference for real‐world sea ice deformation behavior under natural conditions.