Understanding Snowmelt Interaction with the Environment in a Changing Climate: Insights from a Small Coastal Mountainous Catchment in Svalbard

In the face of climate change transforming snow cover and permafrost in the Arctic, it is important to enhance our understanding of how snowmelt interacts with the environment. Here, we use stable isotopes of ¹⁷O, ¹⁸O and ²H coupled with hydro-chemical tracers and process-based modelling, to trace snowmelt from the evolution of the snowpack to river runoff and groundwater recharge in a coastal Arctic environment. The study is based on the data obtained from an unglaciated Fuglebekken catchment of 1.27 km² situated in the southwest Spitsbergen. This area represents sea terraces and coastal mountain catchments that are becoming increasingly common with deglaciation. We reveal the dynamics of the snowmelt partitioning between surface runoff and underground recharge throughout the summer season. Change in isotopic content within the snow profile during snowpack evolution indicates significant fractionation processes. The study underlines the importance of accurately addressing uncertainties when using the isotopic hydrograph separation method and discusses possibilities for tackling these uncertainties.