Simulations of future snow cover and discharge in Alpine headwater catchments

Abstract

Abstract:The snow cover in the Alps is heavily affected by climate change. Recent data show that at altitudes below 1200 m a.s.l. a time-continuous winter snow cover is becoming an exception rather than the rule. This would also change the timing and characteristics of river discharge in Alpine catchments. We present an assessment of future snow and runoff in two Alpine catchments, the larger Inn catchment (1945 km 2 ) and the smaller Dischma catchment (43 km 2 ), based on two common climate change scenario (IPCC A2 and B2 (IPCC, 2007)). [etc]. The changes in snow cover and discharge are predicted using Alpine3D, a model for the high-resolution simulation of Alpine surface processes, in particular snow, soil and vegetation processes. The predicted changes in snow and discharge are extreme. While the current climate still supports permanent snow and ice on the highest peaks at altitudes above 3000 m a.s.l., this zone would disappear under the future climate scenarios. The changes in snow cover could be summarized by approximately shifting the elevation zones down by 900 m. The corresponding changes in discharge are also severe: while the current climate scenario shows a significant contribution from snow melt until middle to late summer, the future climate scenarios would feature a much narrower snow melt discharge peak in spring. A further observation is that heavy precipitation events in the fall would change from mainly snow to mainly rain and would have a higher probability of producing flooding. Future work is needed to quantify the effect of model uncertainties on such predictions.

Importance of maximum snow accumulation for summer low flows in humid catchments

“…Earlier snowmelt onset and thus decrease of minimum streamflow has been observed (Jefferson, 2011) and a further shift of snowmelt towards earlier spring is predicted (Barnett et al, 2005;Bavay et al, 2009;Hanel et al, 2012;Godsey et al, 2014;Blahusiakova and Matouskova, 2015).…”

“…This shift results in a decrease of the fraction of solid precipitation (snow/total precipitation, known as S/P ) and thus in a decrease of snow accumulation especially in midelevation mountain ranges (Knowles et al, 2006;Pellicciotti et al, 2010;Speich et al, 2015). The decrease of S/P will affect groundwater recharge during spring and as a conse-quence also low streamflow values in the subsequent summer period (Bavay et al, 2009;Godsey et al, 2014).…”

Improving the degree-day method for sub-daily melt simulations with physically-based diurnal variations

“…The stations are located at elevations ranging between 1780 and 2300 m on the southwest-faci ng slope and between 2160 and 2430 m on the southeast-faci ng slope. Compare d to previous research conducted at the site scale [36,29] with distributed measurements [12,49,74,2], the locations of the meteorologi cal stations offer a unique opportunity to compare the melt method performanc es relative to temperature measure ments from differing aspects.…”

Soil Moisture & Snow Properties Determination with GNSS in Alpine Environments: Challenges, Status, and Perspectives

“…Alpine3D [46,47] can calculate SWE based on [48] at grid points. Alpine3D is driven by meteorological data, using the SNOWPACK model as the core snow-modeling module.…”