Snowmelt is a very important component of freshwater resources in the polar environment. Seasonal fluctuations in the water supply to glacial drainage systems influence glacier dynamics and indirectly affect water circulation and stratification in fjords. Here, we present spatial distribution of the meltwater production from the snow cover on Hansbreen in southern Spitsbergen. We estimated the volume of freshwater coming from snow deposited over this glacier. As a case study, we used 2014 being one of the warmest season in the 21st century. The depth of snow cover was measured using a high frequency Ground Penetrating Radar close to the maximum stage of accumulation. Simultaneously, a series of studies were conducted to analyse the structure of the snowpack and its physical properties in three snow pits in different glacier elevation zones. These data were combined to construct a snow density model for the entire glacier, which together with snow depth distribution represents essential parameters to estimate glacier winter mass balance. A temperature index model was used to calculate snow ablation, applying an average temperature lapse rate and surface elevation changes. Applying variable with altitude degree day factor, we estimated an average daily rate of ablation between 0.023 m d-1 °C-1 (for the ablation zone) and 0.027 m d-1 °C-1 (in accumulation zone). This melting rate was further validated by direct ablation data at reference sites on the glacier. An average daily water production by snowmelt in 2014 ablation season was 0.0065 m w.e. (water equivalent) and 41.52·106 m3 of freshwater in total. This ablation concerned 85.5% of the total water accumulated during winter in snow cover. Extreme daily melting exceeded 0.020 m w.e. in June and September 2014 with a maximum on 6th July 2014 (0.027 m w.e.). The snow cover has completely disappeared at the end of ablation season on 75.8% of the surface of Hansbreen.
The results from a hydrological monitoring program of Breelva basin (Spitsbergen, Svalbard) have been analysed to improve the understanding of the Werenskiöld Glacier system’s functioning in the High Arctic. Hydrographs of a 44 km 2 river basin (27 km 2 of which was covered by a glacier) were analysed for the period 2007–2012. Seasonal discharge fluctuations were linked to glacier ablation and meteorological parameters, including atmospheric circulation types. A dichotomy was found in the discharge peaks generation during the hydrologically active season, with the main role played by snow and ice melt events during its first part and the rainfall regime dominating its second part. Foehn type strong winds played a significant role in the generation of ablation type floods ( e.g. in August 2011). A simple classification of the runoff regime was applied to the examined six−year period, resulting in the identification of its three types: the ablation type (dominant in 2007 and 2009), the rainfall type (in the years 2011–2012), and the mixed type (during 2008 and 2010). According to publications the river flow season in Spitsbergen begins in June and end with freeze−up in September or at the beginning of October. Recently, this season for Breelva tend to be extended with the mid−May onset and end in the second part of October. A multiannual trend was noted that reflects a growing importance of rainfalls, especially in September. Rainfall waters play a more distinct role in outflow from the Breelva catchment recently.