其他摘要：Our study considers climate change and its influence upon the hydrology and water balance of the glacierized Bayelva watershed in Svalbard. We find that changes are most noticeable within the last 10 years, when winters have become warmer and wetter. The change is most significant during the shoulder months, especially September, when the transition from summer ablation to winter accumulation is taking place. Winter rainfalls, when extreme, produce ground icings and runoff outside the summer period. Dependent upon summer air temperatures, these icings may either melt and produce additional runoff or persist until the following hydrological year. These processes have a direct influence upon the water budget. They represent sources of error for water-balance calculations that either ignore winter runoff events and/or assume water storage is negligible. We show that even when the watershed is underlain by permafrost and accommodates cold-based glaciers, storage can no longer be ignored. Furthermore, we find that the use of a precipitation gradient correction of 19% per 100 m, a gauge catch correction and glacier massbalance data (for snow accumulation and icemelt runoff) should be used for accurate water-balance calculations. We also find that despite sustained glacier retreat, annual runoff volume showed no trend during 1989-2010. Discharge is more variable and longer during the last decade due to the winter rainfalls. Finally, flow recession analyses reveal increasingly efficient evacuation of meltwater from the catchment and the increasing occurrence of a delayed flowpath through the glaciers’ forefield.
其他关键词：Arctic hydrology;water balance;rain on snow;extreme events;Svalbard;climate change
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