HR: 0800h
AN: C21A-1079    [Abstracts]
TI: Parameterization of snow-redistribution by avalanches for regional-scale models of mass and energy balance
AU: * Gruber, S
EM: stgruber@geo.unizh.ch
AF: Laboratoire EDYTEM, Universit‚ de Savoie, Le Bourget-du-Lac Ce, 73376 France
AU: * Gruber, S
EM: stgruber@geo.unizh.ch
AF: Glaciology and Geomorphodynamics Group, Department of Geography, University of Zurich Winterthurerstr. 190, Zurich, 8057 Switzerland
AU: Hasler, A
EM: ahasy@geo.unizh.ch
AF: Glaciology and Geomorphodynamics Group, Department of Geography, University of Zurich Winterthurerstr. 190, Zurich, 8057 Switzerland
AB: The snow cover is a decisive factor of the energy and mass balance of cold mountain regions. Redistribution of snow on steep mountain slopes by avalanches often strongly alters the spatial pattern of snow deposition. Snow patches that melt late in summer below steep slopes have been shown to favour cold ground temperatures and, hence, influence the distribution of permafrost. Many small mountain glaciers obtain a significant proportion of their accumulation from avalanches originating from the rock walls surrounding them. Often, such glaciers are situated entirely below the climatic equilibrium line altitude. Additionally, redistributed snow changes the altitudinal and areal distribution of snow water equivalent and thus also affects the runoff regime in mountain catchments. A multitude of studies and methods use morphometric attributes or model wind fields to simulate snow distribution patterns in mountains on varying scales of sophistication, spatial and temporal resolution. However, most models of snow redistribution by avalanches are far too complex to be included into regional-scale models operating on cell sizes in the order of 10-100 m. A simple array-based algorithm that handles the task of transporting the snow from a source cell to its deposition area is introduced: The TOPMODEL multiple flow-direction algorithm is extended by a deposition function. This multiple flow-direction algorithm with deposition (MFLOWDEP) is a fast and simple way to achieve realistic transport of snow in steep topography and to improve distributed models dealing with alpine snow cover. Application in a simple degree-day model as well as analyses of the sensitivity to cell size are presented. Broader application of the proposed algorithm to e.g. lahars and mudflows is possible but still in an experimental stage.
DE: 0545 Modeling (4255)
DE: 0736 Snow (1827, 1863)
DE: 0742 Avalanches
DE: 0762 Mass balance (1218, 1223)
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
SC: Cryosphere [C]
MN: Fall Meeting 2005