Long-term simulation of snow cover and potential impacts on seasonal soil frost dynamics over croplands across Canada

Abstract

<b><sc>Abstract.</sc></b> Changes in weather patterns due to climate change pose a long-term threat to the ability of soil to retain nutrients or induce trace gas emission. Accurate simulation of overwintering conditions for farmland is crucial for predicting nutrient loss and crop growth under climate change. Snow cover is the common upper boundary condition that impacts the soil freeze-thaw dynamics, and it has been hypothesized that the reduced snow cover due to climate change may increase soil frost depth or duration. Nonetheless, such impact remains poorly understood and is rarely examined for farmland in the long-term experiment due to data scarcity. This paper aims to investigate the overwinter snow cover, soil temperature, and soil frost dynamics with the RZ-SHAW (Root Zone Water Quality Model with integrated SHAW model) in six research farms across Canada over a series of long-term simulations range from 1989 to 2020. The RZ- SHAW scenarios are calibrated and validated against the observed snow depth and soil temperature data. The same calibrated scenarios are then applied to simulate the soil frost depth and duration for each farmland to discover the potential influence of global warming on the soil frost dynamic.