Abstract
The temporal evolution of seasonal snow cover and its spatial variability in environments such as mountains, prairies or polar regions is strongly influenced by the interactions between the atmospheric boundary layer and the snow cover. Wind-driven coupling processes affect both mass and energy fluxes at the snow surface with consequences on snow hydrology, avalanche hazard and ecosystem development. This paper proposes a review on these processes and combines the more recent findings obtained from observations and modelling. The spatial variability of snow accumulation across multiple scales can be associated to wind-driven processes ranging from orographic precipitation at large scale to preferential-deposition of snowfall and wind-induced transport of snow on the ground at smaller scales. An overview of models of varying complexity developed to simulate these processes is proposed in this paper. Snow ablation is also affected by wind-driven processes. Over continuous snow covers, turbulent fluxes of latent and sensible heat, as well as blowing snow sublimation, modify the mass and energy balance of the snowpack and their representation in numerical models is associated with many uncertainties. As soon as the snow cover becomes patchy in spring local heat advection induces the developement of stable internal boundary layers changing heat exchange towards the snow. Overall, wind-driven processes play a key role in all the different stages of the evolution of seasonal snow. Improvements in process understanding particularly at the mountain-ridge and the slope scale, and processes representations in models at scales up to the mountain range scale, will be the basis for improved short-term forecast and climate projections in snow-covered regions.
Highlights
The strong interaction between atmospheric boundary layer and land-surface via energy and mass exchange processes makes the distribution of snow a key element of the Earth system (Roesch et al, 2001; Vaughan et al, 2013) with crucial consequences for the hydrological cycle (Lehning, 2013) and the climate of cold regions (Beniston et al, 2018)
We provide an overview of the current state of knowledge on wind-driven coupling processes between the snow cover and the atmosphere governing seasonal snow cover dynamics, with a special focus on mountaineous regions
Experiments on snow melt dynamics conducted by Mott et al (2017) demonstrated that insufficient representation of sub-grid snow cover fractions on the regional scale and simple gradient-flux relationships at the same time lead to large biases in flux estimates that need to be addressed in atmospheric and hydrological models in future
Summary
The strong interaction between atmospheric boundary layer and land-surface via energy and mass exchange processes makes the distribution of snow a key element of the Earth system (Roesch et al, 2001; Vaughan et al, 2013) with crucial consequences for the hydrological cycle (Lehning, 2013) and the climate of cold regions (Beniston et al, 2018). The coupled snow-atmosphere modeling approach proposed by Vionnet et al (2014) allows to explicitly simulate local cloud dynamical effect and to discuss the relative importance of the different processes influencing the variability of snow accumulation in alpine terrain (Vionnet et al, 2017).
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