HR: 17:45h
AN: H24B-08    [Abstracts]
TI: Inhomogeneous precipitation distribution and snow transport in steep terrain
AU: * Lehning, M
EM: lehning@slf.ch
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research, SLF Davos, Flà¼elastr. 11, Davos, CH-7260, Switzerland
AU: Là¶we, H
EM: loewe@slf.hc
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research, SLF Davos, Flà¼elastr. 11, Davos, CH-7260, Switzerland
AU: Raderschall, N
EM: raderschall@slf.ch
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research, SLF Davos, Flà¼elastr. 11, Davos, CH-7260, Switzerland
AU: Ryser, M
EM: marcdaniel.ryser@gmail.com
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research, SLF Davos, Flà¼elastr. 11, Davos, CH-7260, Switzerland
AB: The inhomogeneous snow distribution found in Alpine terrain is the result of wind and precipitation interacting with the (snow) surface over terrain. We introduce and explain preferential deposition of precipitation as the deposition process without erosion of previously deposited snow and thus in the absence of saltation. A numerical model is developed, describing on a physical basis the relevant processes saltation, suspension and preferential deposition. The model uses high resolution wind fields calculated with a meteorological model (ARPS). The model is used to simulate a 120 hour snow storm period over a steep Alpine ridge, for which also snow distribution measurements are made. The comparison to measurements shows that the model captures the larger scale snow distribution patterns and predicts the total additional lee slope loading well. However, the spatial resolution of 25 m is still insufficient to capture the smaller scale deposition features observed. The model suggests that the snow distribution on the ridge scale is primarily caused by preferential deposition and that this result is not sensitive to model parameters such as turbulent diffusivity, drift threshold, or concentration in the saltation layer.
DE: 0736 Snow (1827, 1863)
DE: 0772 Distribution
DE: 3307 Boundary layer processes
DE: 3322 Land/atmosphere interactions (1218, 1631, 1843)
DE: 3354 Precipitation (1854)
SC: Hydrology [H]
MN: 2007 Fall Meeting