Sea ice, wind waves and coastal erosion in Hornsund, Svalbard

Increasing water levels at the shore can cause coastal erosion, wave overtopping and flooding that threaten communities and infrastructure. More frequent, longer and more severe storm events observed in the North Atlantic sector of the Arctic bring more energetic waves to beaches of western Svalbard. Decreasing extent and duration of the sea ice cover increases potential fetch which makes the waves higher and longer. At the shore, the number of ice-free days per year has increased and coasts that were protected from waves by ice are becoming exposed perennially or over longer time. Modelling suggests that in future the sea ice will continue to decrease while the storminess will further increase. Better understanding the role of sea ice conditions and nearshore wave transformations on wave energy at the Arctic shores is needed to predict coastal hazards under changing climate.

In this study we focus on wave energy delivery to the shores of Hornsund, a ~300 km² fjord of south-western Spitsbergen, Svalbard, and particularly to Isbjornhamna bay in northern Hornsund, where the Polish Polar Station infrastructure is located. We monitor continuously nearshore wind wave conditions and the state of the shore ice, and seasonally the wave run-up and beach morphology. We use three nested SWAN (Simulating WAves Nearshore) models that take low-resolution global wind and wave models and nearshore bathymetry to reconstruct wind wave conditions in the nearshore (~15 m depth) Isbjornhamna. Finally, we use Sentinel-1 SAR data to reconstruct sea ice conditions in Hornsund area which need be incorporated into the wave model. Here we show how our monitoring and modelling scheme facilitates the comprehensive understanding of the nearshore and coastal processes in Isbjornhamna.