Ocean Waves, Sea Ice, and Coastal Protection Along Alaska’s North Slope

Lucia Hosekova, Applied Physics Laboratory, Seattle, WA, United States; University of Reading, Reading, United Kingdom, Nirnimesh Kumar, University of Washington, Department of Civil & Environmental Engineering, Seattle, WA, United States, W. Erick Rogers, Naval Research Lab, Stennis Space Center, MS, United States and James M Thomson, Applied Physics Laboratory University of Washington, Seattle, WA, United States
Abstract:
The coastlines in the north of Alaska are eroding at increasing rates, leaving coastal communities vulnerable to floods and storm surges. A key contributing factor is the decrease in Arctic sea ice levels which allows for surface waves to grow over large fetches in the open ocean and reduces coastal protection provided by shore-fast ice. A process-based representation of wave forcing and sea ice interactions near the coastlines is needed to understand and quantify the changes to the Alaskan coast along the north slope.

In this study, we use the wave model SWAN, recently updated to account for sea ice effects, to simulate nearshore wave conditions in the southern Beaufort Sea. Model wave boundary conditions are provided by a regional WAVEWATCH III® model, and the sea ice concentration is obtained from the Navy’s Arctic Cap Nowcast/Forecast System. Modeled bulk wave parameters are validated against August 2014 in situ measurements along the shelf break and in the nearshore. We compare wave simulations with and without sea ice effects to determine the role of ice in protecting the northern Alaskan coast. Particularly, we quantify changes in wave radiation stress gradients, which drive longshore velocities and longshore sediment transport.

Funded by the National Science Foundation and the Office of Naval Research.

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