Snow particle fragmentation enhances snow sublimation

Abstract. Fragmentation of snow particles – wherein freshly deposited dendritic crystals are rapidly transformed into smaller, rounded grains through collisions with the surface and other particles during drifting and blowing snow – plays a critical role in governing snowpack evolution and transport dynamics. However, existing models of drifting and blowing snow often neglect the effects of snow particle fragmentation, introducing uncertainties in the prediction of flow dynamics and sublimation rates. In this study, we incorporate a snow particle fragmentation model into a well-developed blowing snow model to quantitatively investigate the influence of fragmentation under varying wind conditions. Our results reveal that fragmentation within the saltation layer generates smaller particles, leading to an increase in mass flux and subsequently enhancing sublimation rates in drifting and blowing snow. The effects of fragmentation on sublimation are more pronounced for suspension particles than for saltation particles, particularly when the friction velocity is less than 0.3 m s−1. This work highlights the critical role of collision-induced fragmentation, wherein dendritic crystals are shattered into smaller particles during transportation. This quantitative assessment of fragmentation impact on snow sublimation underscores its importance for improving the physical representation of drifting and blowing snow in snow transport models and for potential applications in snow hydrology and climate modeling.