Hydroclimate Reconstruction in the Changing High Arctic Maritime Environment, Linnédalen, Svalbard

Few places on the planet are experiencing the consequences of climate warming more quickly or drastically than the Arctic. The marine and terrestrial environments of the Svalbard Archipelago in the Norwegian high arctic clearly show widespread impacts. Warmer and wetter fall and winter seasons have shifted the annual hydrological regime from one formerly dominated by springtime snowmelt to one that is less predictable and increasingly dominated by late summer and fall rain events. Given that rainfall intensity and frequency are expected to increase significantly in the coming century, awareness of the changes and their consequences is vital for predictive models and general preparation for the future. Monitoring and analysis of annual lacustrine sediment yield within Linnévatnet, a glacier-fed lake on the west coast of Svalbard, provides a key to understanding recent changes in the environmental factors driving sedimentation and the timing of sedimentation events. Environmental processes and sedimentation patterns monitored since 2004 in and around Linnévatnet record a widespread shift in hydrological regime seen over the past decades throughout the Arctic. Although six of the last nine years have been dominated by shoulder season hydrology, field measurements, geochemical and mineralogical analysis of sediment traps indicate that the 2018–2019 hydrological year was predominantly a snowmelt-dominated regime, with 88% of sediment contributed from spring and early summer nival flooding. Additionally, data from the past hydrological year show the second largest sediment accumulation since 2003/2004, consistent with a trend of increasing sediment yield seen throughout the longer-term period of monitoring.