Abstract

Skillful nearshore wave forecasts are critical for providing timely alerts of hazardous wave events that impact navigation or recreational beach use. While typical forecasts provide bulk wave parameters (wave height and period), spectral details are needed to correctly predict wave and associated circulation dynamics in the nearshore region. Currently, global wave models, such as WAVEWATCH III, make spectral predictions, but do not assimilate regional buoy observations. Here, Spectral Wave Residual Learning Network (SWRL Net), a fully convolutional neural network, is trained to take recent WW3 forecasts and buoy observations, and produce corrections to frequency-directional WW3 spectra, transformed into directional buoy moments, for up to 24 hours in the future. SWRL Net is trained with 10-years of collocated NOAA’s WW3 CFSR Reanalysis predictions and buoy observations at three locations offshore of the US western coast. At buoy locations SWRL Net residual corrections result in wave height root mean square error (RMSE) reductions of 23-50% in the first 6 hours and 10-20% thereafter. Sea frequencies (5-10 seconds) show the most improvement compared to swell (12-20 seconds). SWRL Net reduces mean direction RMSE by 28-54% and mean period RMSE by 20-56% over 24 forecast hours. While each model is trained and tested at independent locations, SWRL Net exhibits generalization when introduced to data from other locations, suggesting future development may be composed of training sets from multiple locations.

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Footnotes

Computer Science, Western Washington University, Bellingham, WA 98225

Geology, Western Washington University, Bellingham, WA 98225

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Civil and Environmental Engineering, University of Washington, Seattle, WA 98195

Computing & Analytics Division, Pacific Northwest National Laboratory, Richland, WA 99354