Mountain Snow Distribution and how it may Change in the Future
The spatial distribution of snow in the mountains is highly heterogeneous, and processes behind this heterogeneity are not yet understood quantitatively. Based on (i) increasing accuracy and spatial coverage of remotely sensed snow depth maps, which have become available recently, (ii) improved atmospheric modeling of precipitation and particle dynamics, and (iii) better distributed measurements of solid precipitation (radar), it is possible to improve the characterization of processes leading to the observed snow distributions. We present results that show the relative importance of local precipitation variability, preferential deposition of snow, and wind and gravity driven snow transport. Current evidence suggests that these processes significantly contribute to shaping the alpine snow distribution. On average snow depth and water equivalent increase up to a certain elevation showing a distinct maximum, before decreasing at ridge/summit elevations.. Additionally, we address the impact of climate change and show how much different elevations (and climate zones) in the Alps are affected by global warming as predicted by various regional climate models. Also snowmelt dynamics and runoff generation are investigated on the sub-catchment scale and related to forcing of local climatic conditions. It is concluded that above the tree-line, snow distribution and the relative importance of associated processes is not expected to change significantly, despite the fact that warming will lead to a strong decrease in snow at the mid-altitude range.