Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 466–472.

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Variability of runoff from Alpine basins

DAVID N. COLLINS

Alpine Glacier Project, School of Environment & Life Sciences, University of Salford, Salford Crescent, Manchester M5 4WT, UK

d.n.collins@salford.ac.uk

Abstract Year-to-year variability of runoff from three moderately-glacierized (36–66% ice cover) and two (near-)ice-free (0–1.9%) headwater basins in the Alpine Aare and Rhône basins, Switzerland, was assessed for 50 years from 1956 to 2005. Variability, as coefficient of variation, was less in moderately-glacierized than in (near-) ice-free precipitation-influenced basins, but increased in basins with between 40 and 66% glacierization as energy-availability for snow/icemelt dominated. Mean summer air temperature increase of 1.13°C between 1956–1980 and 1981–2005, coupled with a 13% reduction in mean total annual precipitation, was associated with decreased runoff variability in basins having between 0 and 40% glacierization but with increased variability in more highly glacierized basins.

Key words coefficient of variation; runoff variability; glacierized basin; climatic variation

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