Long-Term Wave Properties Around Funafuti, Tuvalu from Satellite Imagery

The coastal region of island nations is subjected to frequent erosion or accretion and is thus considered vulnerable. Numerical models have been used to investigate and predict coastal environments including coastline changes. However, many Pacific Island Countries (PICs) have narrow and low land areas and global ocean models like ERA-5 do not consider that bathymetry. Therefore, the model data are not enough to analyze wave affects to coastline changes. In this work, we developed a method to extract reliable wavelength and wave direction from optical satellites and validated those parameters with ERA-5. Tuvalu, an atoll nation in the Southwest Pacific, is selected as the study region, and multiple satellite data sets are used in this work, which include medium-resolution Sentinel-2 and Landsat-8/9 images. With detailed wave properties, we analyzed a long-term trend from 2013 to 2023. The results of this study will provide valuable advantages for decision-making by accurate information about the coastal environment.