Nearshore wave time-series along the coast of Alaska computed with a numerical wave model

Alaska's Arctic coast has some of the highest erosion rates in the world. Erosion in the Arctic is primarily driven by permafrost thaw and wave activity. The warming climate decreases sea ice coverage, resulting in an increase in wave energy. To overcome the lack of available observational wave data in the nearshore, waves were downscaled with a numerical wave model (SWAN) utilizing several model domains along the coast. For each domain, the model was forced at the open boundary with over 2000 representative sea states, which are likely combinations of significant wave heights, mean wave periods, and mean wave directions in addition to wind speed and directions. The wave and wind parameters at the SWAN model open boundary were inferred with a multivariant maximum-dissimilarity algorithm for a.) the hindcast period 1979-2023 from ERA5 reanalyzed winds and waves and b.) the historical (1979-2013) and future (2020-2050) periods from wave time-series computed with a global WAVEWATCHIII (WWIII) model and wind conditions from the Coupled Model Intercomparison Project (CMIP6). The SWAN runs created a downscaled wave database (DWDB) at each grid point which was used to reconstruct time series in the nearshore along the 5 and 10 m isobaths at locations approximately 400 m apart and corresponding to transects from the U.S. Geological Survey (USGS) developed Digital Shoreline Analysis System (DSAS).