CoAuthors

Florence Toublanc (NOVELTIS, France); Florent Lyard (LEGOS/CNRS/OMP, France); Gérald Dibarboure (CNES, France); Nicolas Picot (CNES, France); Thierry Guinle (CNES, France)

Coastal processes (tidal currents, storm surges, waves) are highly dependent on bathymetry and directly impact offshore and coastal activities and studies. Many studies and applications lie on a growing modelling effort of the ocean and the limited accuracy of bathymetry, especially on the continental shelves, contributes to degrade numerical model performance despite significant use of in-situ and satellite measurements assimilation. In particular, the tidal models are very sensitive to the bathymetry accuracy on the shelves, where the ocean tides show the largest amplitudes and are strongly non-linear. This has a direct impact on the quality of the altimetry sea surface heights as the tide correction is one of the largest corrections on the shelves, ranging from several centimetres to several metres.
Various sources of bathymetry data exist but many regions remain not well known because of too sparse measurements, data access limitation or large temporal variability of the seabed dynamics. In this context, a project was launched by CNES with the aim to improve the bathymetry in the North-East Atlantic Ocean and on the Indonesian continental shelves. The work was divided in several steps: 1/ an inventory of existing datasets and methods to derive the bathymetry on the shelves ; 2/ the integration of the collected datasets into a reference global bathymetry dataset ; 3/ the evaluation of this new bathymetry dataset through hydrodynamic modelling and the production of regional tidal models.
This paper presents the methodology and the most recent results obtained within this project.