https://doi.org/10.5194/tc-16-4201-2022

Dutch, V. R., Rutter, N., Wake, L. et al. incl. Hould Gosselin, G., Sonnentag, O.: Impact of measured and simulated tundra snowpack properties on heat transfer, The Cryosphere, https://doi.org/10.5194/tc-16-4201-2022

Snowpack microstructure controls the transfer of heat to, and the temperature of, the underlying soils. In situ measurements of
snow and soil properties from four field campaigns during two different winters (March and November 2018, January and
March 2019) were compared to an ensemble of CLM5.0 (Community Land Model) simulations, at Trail Valley Creek,
Northwest Territories, Canada. Snow MicroPenetrometer profiles allowed snowpack density and thermal conductivity to be
20 derived at higher vertical resolution (1.25 mm) and a larger sample size (n = 1050) compared to traditional snowpit
observations (3 cm vertical resolution; n = 115). Comparing measurements with simulations shows CLM overestimated snow
thermal conductivity by a factor of 3, leading to a cold bias in wintertime soil temperatures (RMSE = 5.8 ℃). Bias-correction
of the simulated thermal conductivity (relative to field measurements) improved simulated soil temperatures (RMSE = 2.1 ℃).
Multiple linear regression shows the required correction factor is strongly related to snow depth (R2 = 0.77, RMSE = 0.066)
25 particularly early in the winter. Furthermore, CLM simulations did not adequately represent the observed high proportions of
depth hoar. Addressing uncertainty in simulated snow properties and the corresponding heat flux is important, as wintertime
soil temperatures act as a control on subnivean soil respiration, and hence impact Arctic winter carbon fluxes and budgets.

Northern-Water-Futures, Refereed Publications

https://doi.org/10.5194/tc-16-4201-2022, Accepted
Code and data to produce figures are available at
https://github.com/VDutch/TVCSnowCLM
and
https://doi.org/10.5281/zenodo.7137729