Sensitivity of glacier runoff to summer snowfall events

Abstract

In order to investigate the effect of changing precipitation type on glacier discharge due to air-temperature changes, the relation between summer snowfall and runoff is surveyed for the Vernagtbach basin, Austria, (2640–3630ma.s.l.; ~72% glaciated) for the period 1976–2005. Precipitation data were evaluated for each ablation season with respect to amount and type; the latter derived mainly from daily photographs of the catchment, but validated over 4 years with additional meteorological data. Winter snowfall amounts were determined on the basis of mass-balance measurements. Average ablation period air temperature showed a rise of 1.5 K from 1976 to 2005, and runoff increased from about 1100 mmw.e. to 2200 mmw.e. Snowfall amounts during the ablation period decreased between 1976 and 1991, but increased from 1992 to 2005, indicating a large year-to-year variation. The number of days with snowfall varies even more, with no clear trend discernible. The evolution of runoff is only partly explained by precipitation type during the ablation season, and accumulation amounts during winter deliver a not unambiguous picture. More important is the development of the ablation area from about 20% of glacier size in the 1970s to 100% in 2003.

Effects of lake‐groundwater interaction on the thermal regime of a sub‐alpine headwater stream

“…In other mountain regions, such as the Vernagtbach basin in Austria, there are years when solid precipitation accounted for up to 70% of total precipitation during the ablation season. During the same period, there were up to 50 days with snowfall (Escher‐Vetter & Siebers, 2007). In the Hathataga catchment, solid precipitation accounted for 23% of total precipitation from May to September 2019 with 20 days of snowfall.…”

Relevance and Scale Dependence of Hydrological Changes in Glacierized Catchments: Insights from Historical Data Series in the Eastern Italian Alps

“…Temperature was 2 • C lower than in the 1940s and 2000s between March and September, and precipitation was higher, in particular during winter and spring. The solid fraction was also larger, principally in summer, with important effects on the summer balance of glaciers [53,67].…”

Reconstructing five decades of sediment export from two glaciated high-alpine catchments in Tyrol, Austria, using nonparametric regression

“…This entails crucial changes in albedo and therefore intensified ice melt and thinning of firn areas due to rising energy absorption at the glacier surface (Escher-Vetter, 2007;Braun et al, 2007). We interpret this as a regime shift as summer mass balances continue to be lower than before 1981 615 although (July) temperatures decrease again, with the exception of 1984, which was characterized by a relatively high number snowfall days during the ablation period (Escher-Vetter and Siebers, 2007).…”

“…Escher-Vetter (2007 and Abermann et al (2009) have also shown that mass loss started in 1981 at both glaciers, resulting from negative 610 summer balances. With respect to the Vernagtferner, the drastically higher ablation area ratio of almost 80 % in 1982 as compared to around 25 % in the preceding years (Escher-Vetter and Siebers, 2007) indicates that large areas of the glacier became snow-free in 1982. This entails crucial changes in albedo and therefore intensified ice melt and thinning of firn areas due to rising energy absorption at the glacier surface (Escher-Vetter, 2007;Braun et al, 2007).…”