Snow surface erosion measurements in a cold wind tunnel
Abstract
The quantification of snow erosion in cold wind tunnels is traditionally performed with particle counting methods that are limited to relatively small volumes at one point. Field studies with terrestrial laser scans are a method to observe the evolution of the snow surface over a large area but lack high temporal resolution. We introduce a Kinect sensor as a new tool to observe the snow surface height during events of drifting snow, enabling relatively resolutions both in time and space. Multiple experiments consisting of increasing wind-speed steps sweeping over the threshold velocity towards strong saltation were performed. Alongside the snow surface height, traditional particle counting methods as well as measurements of the flow properties were recorded. Results of this analysis show that for low wind speeds, there is a balance in erosion and accumulation on the snow surface, while with increasing wind erosion dominates. Furthermore we found that the mean mass flux calculated from the snow surface change correlates well with the mean mass flux in the saltation layer (r2 = 0.91). Peaks in erosion are wide and in the order of 10 s while the following peak in saltation mass-flux is much shorter. Distinct peaks in the saltation are accompanied with periods of strong erosion before and after. Evaluating differences in snow surface height, a quantitative mass balances can be calculated. The recorded data sets enable a quantification of the eroded snow masses in comparison with the transport in the saltation layer and therefore describe the interaction of processes in the saltation layer with those on the snow.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.C23B0749C
- Keywords:
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- 0736 Snow;
- CRYOSPHEREDE: 0740 Snowmelt;
- CRYOSPHEREDE: 0742 Avalanches;
- CRYOSPHEREDE: 1863 Snow and ice;
- HYDROLOGY