The ice cap Vestfonna in the northern Svalbard archipelago is one of the largest ice bodies of the European Arctic (∼2400 km2), but little is known about its mass balance. We model the climatic mass balance of the ice cap for the period September 2000 to August 2009 on a daily basis. Ablation is calculated by a spatially distributed temperature‐radiation‐index melt model. Air temperature forcing is provided by ERA‐Interim data that is downscaled using data from an automatic weather station operated on the ice cap. Spatially distributed net shortwave radiation fluxes are obtained from standard trigonometric techniques combined with Moderate Resolution Imaging Spectroradiometer‐based cloud cover and surface albedo information. Accumulation is derived from ERA‐Interim precipitation data that are bias corrected and spatially distributed as a function of elevation. Refreezing is incorporated using the Pmax approach. Results indicate that mass balance years are characterized by short ablation seasons (June to August) and correspondingly longer accumulation periods (September to May). The modeled, annual climatic mass balance rate shows an almost balanced mean of −0.02 ± 0.20 m w.e. yr−1 (meters water equivalent per year) with an associated equilibrium line altitude of 383 ± 54 m above sea level (mean ± one standard deviation). The mean winter balance is +0.32 ± 0.06 m w.e. yr−1, and the mean summer balance −0.35 ± 0.17 m w.e. yr−1. Roughly one fourth of total surface ablation is retained by refreezing indicating that refreezing is an important component of the mass budget of Vestfonna.

Digital terrain models of the southern Chilean ice cap Gran Campo Nevado reflecting the terrain situations of the years 1984 and 2000 were compared in order to obtain the volumetric glacier changes that had occurred during this period. The result shows a slightly negative mean glacier change of 3.80 m. The outlet glacier tongues show a massive thinning, whereas the centre of the ice cap is characterized by a moderate thickening. Thus a distinct altitudinal variability of the glacier change is noticed. Hypothetically this could be explained by the combined effects of increased precipitation and increased mean annual air temperature. Both to verify and to quantify this pattern of climatic change, the mean glacier change as well as its hypsometric variation are compared with the results of a degree-day model. The observed volumetric glacier change is traced back to possible climate forcing and can be linked to an underlying climate change that must be comparable with the effects of a precipitation offset of at least 7–8% and a temperature offset of around 0.3 K compared to the steady-state conditions in the period 1984–2000.

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Vestfonna ice cap, northeastern Svalbard, is one of the largest ice bodies in the European Arctic, but little is known about the evolution of its mass balance. This study presents a reconstruction of the climatic mass balance of the ice cap for the period 1979/80-2010/11. The reconstruction is based on calculations using a mass-balance model that combines a surface-elevation-dependent accumulation scheme with a spatially distributed temperature-index ablation model that includes net shortwave radiation. Refreezing is included, based on the basic Pmax approach. The model accounts for cloud-cover effects and surface albedo variations that are calculated by a statistical albedo model. ERA-Interim derived air temperature, precipitation and total cloud-cover data are used as input. Results reveal a mean climatic mass-balance rate of +0.09 ± 0.15 m w.e. a–1 for the study period. Annual balances show a slight, insignificant trend towards less positive values over the study period. Refreezing is estimated to contribute about one-third to annual accumulation, and a significant positive trend in refreezing is present over the study period. The modelling results reveal a significant steepening of the climatic mass-balance gradient and indicate a lengthening of the characteristic 3 month ablation period in recent years.

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