Looking at the Shape of the Sea Floor to Understand Beach Erosion in Kerala

Abstract

I used free satellite data from the Copernicus Marine Service to look at the depth of the sea close to seven beaches in Kerala. Four of these beaches are known erosion hotspots and three are mostly stable. For each beach I drew a line from the shore out to sea and calculated the average slope of the sea floor over the first one, two, and three kilometers. The results do not show a clean pattern. Some eroding beaches have steep sea floors, but the steepest short slope in my sample belongs to a stable beach, and one eroding beach has the gentlest slope. I conclude that nearshore bathymetric slope appears to be one possible factor associated with erosion at some Kerala beaches, but the observed exceptions demonstrate that bathymetry alone cannot explain erosion. This upload includes the final research report (PDF), the bathymetry map (Figure 1), the depth profiles (Figure 2), and the slope metrics table (CSV). Note on raw data: The raw NetCDF bathymetry subset is not included in this upload to save space. The original global dataset is openly available from the Copernicus Marine Service (DOI: 10.48670/mds-00364). The subset used in this study covers the Kerala coast (Longitude 74.5 to 77.2, Latitude 8.0 to 12.6) from the merged static product.