The Compound Impacts of Changing Temperature and Snow Cover on Freeze and Thaw Patterns across Quebec

Seasonal Freeze-Thaw cycles (FT) is a key to environmental processes and socioeconomic activities across northern latitudes. The large-scale dynamics of FT are mainly governed by air temperature and snow depth. We argue that this physical control can be empirically characterized, represented, and simulated by the trivariate dependence structure between FT, temperature, and snow depth. To showcase this, we consider the gridded data of these variables over Quebec, Canada, and use canonical vine copulas to formulate the trivariate interdependence between FT, temperature, and snow depth in different grids and ecozones. Our results reveal different dependence structures across Quebec ecozones, pointing at the role of landscape in regulating the impacts of snow depth and temperature on FT. Having the trivariate dependence, we use a bottom-up impact assessment approach to address the alterations in FT characteristics under single and compound changes in the temperature and snow depth.