Spatiotemporal dynamics of snow erosion, deposition and horizontal mass flux

Abstract

The quantification of snow transport, both in wind tunnels and the field, apply particle counting methods limited to punctual sampling of relatively small volumes. Particle counting can only capture horizontal mass fluxes, failing to measure snow erosion or deposition. Herein, we present a novel low-cost sensor tool, based on a Microsoft Kinect, adapted to capture snow surface changes during snow drifting at unprecedented spatial and temporal resolutions. In the wind tunnel setting of these experiments we observe a balance between erosion and deposition at low wind speeds, while erosion is dominant at higher wind speeds. Significant differences in power spectral densities of surface mass flux and horizontal particle mass flux are observed. We show that for the saltation-length-scale parameter λ = 1, the integrated particle flux can be used to estimate the total surface mass flux in the wind tunnel. This provides an important basis to interpret mass flux measurements in the field.

On the relative importance of saltation and suspension for aeolian snow mass transport

“…During snow transport, mid-air particle motion can be divided into saltation and suspension, considering that this designation plays a useful role in simplifying the process for modelling and understanding the hydrological, glaciological or climatological processes (Blöschl et al, 2019;Crivelli et al, 2019;Essery et al, 1999;Lehning et al, 2008;Palm et al, 2017;Zhou et al, 2014). Similar with windblown sand movement, in snow transport, saltation is defined as the regular hop movement of near surface particles if the inertia of the particles is sufficient to resist turbulent fluctuations (e.g., particles with larger grain size or under lower wind speed), and on the other hand, suspension refers to the long-distance (time) transport of smaller particles owing to stronger turbulence (Bagnold, 1941).…”