Arctic Coastal Observing: Assimilating Buoy vs. Fiber Cable Data into Wave Forecast Model

Over the past decade, significant progress has been made in the development of regional wave observational systems. In particular, the Backyard Buoys program deployed multiple wave buoys along the Alaskan Coast to collect real-time wave spectra. In parallel, the expansion of the subsea fiber optic cable network around Alaska has provided a potential new source for high-resolution Significant Wave Height (SWH) observations. In this study, we conduct Observing System Simulation Experiments (OSSEs) to quantify the potential forecasting skill of different observational configurations, including a moored buoy, a single optical cable, and a hypothetical cable network. We use the SWAN wave model configured for the regional domain along the Northern Alaskan Coast and equipped with an extension of the a4Dvar approach, which allows optimization of both the initial conditions and wind forcing. In the OSSEs, it was found that assimilation of the SWH from the network of optical cables provides the most accurate wave forecast of SWH for regular wind conditions, but assimilation of spectral wave observations from the moorings significantly outperforms the skill of a single-cable platform and provides better control of wind forcing and wave direction, especially for stronger winds. In the second part of the study, the same approach was applied to real observations from the Oliktok Point region. Experiments with real observations from the 37 km long optical cable and wave mooring agree well with the main conclusions from the OSSE results.