Coastal morphology from space: A showcase of monitoring the topography-bathymetry continuum

Abstract

With a large part of the world's population residing in coastal areas, and largely depending on the coastal environment, monitoring natural and human-induced coastal changes are paramount to understand the dynamic and vulnerability of these coastal systems/communities. To understand changes in coastal areas, e.g. environmental and social resilience to environmental change, local measurements are inadequate. Such large-scale issues can only be addressed with perhaps less accurate but large scale measurements from space. Considering vulnerability or exposure to coastal flooding, both the bathymetry (underwater) and topography (above water) are vital boundary conditions to understand and accurately estimate impacts on short (storms) and long (inter-seasonal) time-scales. In this work, we estimate the coastal bathymetry and topography with the optical VENμS satellite for every single overpass at the Field Research Facility of the US Army Corps of Engineers at Duck, NC. The experimental VENμS satellite enables estimation of the topography and bathymetry by two repetitive identical images with a small time-lag. This capability proofs to result in topographies with a few meters accuracy and the bathymetry estimation is at best a few decimetres accurate. As a base for future Earth Observation missions such as Landsat or Sentinel 2, VENμS shows that higher resolution imagery (5 m), repetitive bands and a revisit time of only 2 days, enables unprecedented land/sea monitoring.