“Assessing the wave power density in the Atlantic French façade from high-resolution CryoSat-2 SAR altimetry data”

The wave energy resource potential and trends are assessed in coastal areas of the Atlantic French Façade. High-resolution satellite altimetry sea state estimates (significant wave height and backscatter coefficient) are used, taking advantage of the time and spatial coverage of ESA's CryoSat-2 mission data processed with the coastal zone SAMOSA + waveform retracker algorithm. Due to this novel retracker specifically designed for challenging regions like the coastal zone, the successful measurements of the significant wave height in the coastal zone allows us to solve previously difficult coastal issues such as land and calm water interference in the altimetry footprint. The study comprises 12 years, from January 2011 to December 2022, and applies a relatively simple empirical model to estimate the wave power density. Results are analyzed by season, showing the time of the year and location where the resource is abundant and identifying potential reserves of wave power. The highest value of the mean wave power density (27.1 kW/m) over the 12 years is found in the western sector and to the south of Belle-Île-en-mer, whereas the autumn, in which sea state conditions are less harsh for the extraction activity, appears as the most favorable season for extracting the wave resource. In conclusion, according to the estimated positive trend of wave power density, the wave resource is abundant in nearshore regions of the Atlantic French Façade and promising in view of its future exploitation. The study highlights the importance of an innovative methodology and the role of satellite data in enhancing the accuracy of wave energy assessments.