Evaluating the Aggregate-Scale Thermal Conductivity of Arctic Sea Ice Snowcover

Snow's insulating and reflective properties substantially influence Arctic sea ice growth and decay. Here we present the results of two winter-long field experiments conducted in Utqiaġvik, AK. The experiments seek to better quantify the role of snow in insulating the ice and controlling growth during winter. We present detailed observations of the evolving snow stratigraphy and underlying ice growth over ~1km² domains through the duration of the winter. Terrestrial lidar is used to observe snow surface morphology at cm-scale as the snowpack evolves. Thousands of observations of snow properties, including density, grain size/structure, thermal conductivity, and hardness, are used to track properties for each accumulated layer. Data sets are combined to produce a cm-scale model of evolving snowpack properties over the two ~1km²-scale domains. We find that meaningful changes in the snowpack properties are primarily event driven, with only a handful of snowstorms, wind events, and melt/rain events exerting the majority of control over the snowpack state. The outsize impact of individual events suggests inter-annual variability in snow pack properties may be large. We also evaluate the impact of wind-driven spatial redistribution of snow into dunes and drifts. The distribution of a snow cover governs its aggregate scale thermal resistance. We integrate the data from this experiment with prior studies and a resolved scale snow model to address the question: How much variability in ice growth is controlled by inter-annual variability in snowpack redistribution?