GEBCO and EMODnet-Bathymetry hand in hand: Improving global and regional bathymetric models of European waters

Wednesday, 17 December 2014
Thierry Schmitt, French Hydrographic Service, Brest, France and Pauline Weatherall, British Oceanographic Data Center, Liverpool, L3, United Kingdom
GEBCO (www.gebco.net) provides a unique global Digital Terrain Model (DTM) at 30 arc-second intervals (~1km horizontal resolution). Recognising the importance of regional expertise, GEBCO is collaborating with regional groups to help to continually improve its global model.

Thanks to the European initiative EMODnet (www.emodnet-hydrography.eu), data providers from more than 30 organisations are working to build a regional DTM at 1/8th arc-minute (~ 250 meters resolution) for European waters; from the Norwegian and Icelandic Seas, through the Baltic, Celtic and North Seas to the Black Sea and Mediterranean Sea.

With the aim of producing harmonised products and to prevent any duplication of effort, GEBCO and EMODnet are working together to build an authoritative DTM for European waters. This consists of the following steps:

  1. The Emodnet group has generated a Digital terrain model (2013 version) for European waters, with gaps between data sources.
  2. The EMODnet (2013) DTM has been used to update GEBCO’s global grid using the remove-restore procedure involving the generation of a difference grid between the EMODnet 2013 and the initial GEBCO grids, which is then added on top of the initial GEBCO grid.
  4. When compiling a new 2014 version of the EMODnet DTM, data gaps are filled with the new GEBCO grid.

As a result of this collaboration and the process described above, the latest (2014) versions of both grids show a marked improvement in their precision and continuity.

Repeating this procedure for the future releases of EMODnet and GEBCO bathymetric grids will help improve knowledge of the bathymetry of European waters while providing a fit-for-purpose and consistent grid to users.