Abstract
AbstractThe influence of meteorological variables on snow/ice melting has been analyzed for two very contrasting months, in summer 2006, on Glacier de Saint-Sorlin, French Alps. July 2006 was the warmest July since 1950, and August 2006 was the coldest August since 1979. The total energy available for melting was just over half as much in August as in July, due to a sharp decrease in net shortwave radiation and in turbulent flux. This decrease of net shortwave radiation was mainly controlled by a strong increase in albedo responsible for an increase of reflected shortwave radiation, as well as by a reduction in incident shortwave radiation. During the two months, net longwave radiation remained almost unchanged. The mass balance computed from energy-balance modelling or with a degree-day approach was in good agreement with measured mass balance. Differences were attributed to space and time surface aspect variations which mainly controlled the observed mass balance.
Highlights
Mass balance of temperate glaciers is very sensitive to variations in local meteorology
In J06, degree-day and energy-balance calculations were in very good agreement with measurements: a total of 1.16 m w.e. was measured with the sonic ranger, 1.23 m w.e. was calculated with the degree-day model and 1.17 m w.e. was calculated with the surface energy balance (+6% and < +1%, respectively)
The contribution of the turbulent fluxes of J06 was 21%, explaining 0.24 m w.e. of the mass balance, and cannot be neglected
Summary
Mass balance of temperate glaciers is very sensitive to variations in local meteorology. The topic of this work is the relationship between meteorological variables and the snow/ice ablation on Glacier de Saint-Sorlin, French Alps, during two very contrasting months in 2006 (July and August). For this purpose, radiative surface energy fluxes have been measured and turbulent fluxes calculated with a high temporal resolution (half-hourly means). This paper aims to compare the performance of the two methods and explains the importance of space and time surface aspect variations in both calculations
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