The influence of tidal currents and sea ice on wave dynamics in Cook Inlet, Alaska

Abstract

Cook Inlet, Alaska is a unique tidal estuary with extreme tidal regimes and the presence of seasonal ice coverage. In this study, the wave dynamics of Cook Inlet are explored through analysis of in-situ wave observations and spectral wave model simulations. The analysis first assesses the wave climate from an existing dataset — showing low-energy wave conditions as a mean state for the upper and lower inlets. Following, wave observations within the inlet are analyzed to reveal modulation by tidal constituents. Finally, a region-specific, ocean circulation coupled, spectral wave model is run over a storm event with current and ice forcings present. This simulation reveals that under extreme wind conditions, large waves can exceed 2 m and 6 m in the upper and lower inlet sections. Simulations results demonstrate that increases in significant wave height up to 1 m are observed due to the effects of wave–current interaction on opposing current gradients. This analysis provides insight into how the tidal phase can amplify or diminish wave energy over large extents of the inlet and the role sea ice plays in limiting regional wave energy. These outcomes demonstrate the combined influence of environmental variables current, water levels, and ice influencing wave dynamics and stress the importance of their implementation in wave modeling frameworks where applicable.