WCD-06. Winter snow thermal conductivity and conductive fluxes in the Central Arctic

Abstract
Quantifying the exchanges of energy at the surface is crucial for understanding how the Arctic evolves on seasonal to interannual timescales. During the Arctic winter, net longwave radiation and turbulent fluxes are balanced by conduction at the surface. Vertical conduction depends on both temperature gradients through sea ice and snow and their thermal conductivities. Snow thickness and thermal conductivity both vary widely in space and time, with snow thermal conductivity varying by a factor of six depending on snow conditions. However, most forecast and climate models use a single value for snow thermal conductivity despite the known variability. Using novel observations from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, we derive thermal conductivity estimates that are used to calculate conductive fluxes during winter. We characterize the variability of both snow thermal conductivity and conductive fluxes due to environmental conditions. We further vary snow thermal conductivity in a coupled regional forecast model. Changing snow thermal conductivity impacts not only the magnitude of conductive fluxes, but also the sensitivity of other surface fluxes to atmospheric forcing.