Conditions for accessing the KNMI/ERA-40 Wave Atlas

The KNMI/ERA-40 Wave Atlas available on this server is provided freely for research purposes. Before accessing the KNMI/ERA-40 Wave Atlas please read the conditions below and acknowledge that you accept them.


  1. The KNMI/ERA-40 Wave Atlas available on this server may be used freely for research only. Commercial use of the data is not allowed.
  2. Research is understood as any project organised by a university, scientific institute or similar (private or institutional), for non-commercial research purposes only. A necessary condition for the recognition of non-commercial purposes is that all the results obtained are openly available at delivery costs only, without any delay linked to commercial objectives, and that the research itself is submitted for open publication.
  3. Although every care has been taken in preparing the KNMI/ERA-40 Wave Atlas, we cannot guarantee that the data are correct in all circumstances; neither do we accept any liability whatsoever for any error or omission in the data, or for any loss or damage arising from its use. Known caveats are:
    1. The atlas statistics are based on data averaged on a 1.5°x1.5° area or equivalently a period of about 3 hours, and could be exceeded at short time/space scales.
    2. The ERA-40 model does not account for shallow water effects and therefore the atlas statistics are only valid in deep water regions.
    3. Due to resolution, tropical cyclones are not resolved by the ERA-40 system. Therefore, the statistics for the regions of the tropical storms may be too low.
  4. Any person extracting data from the KNMI/ERA-40 Wave Atlas will accept responsibility for informing all data users of these conditions.
  5. Data from the KNMI/ERA-40 Wave Atlas must not be supplied as a whole or in part to any third party without our authorisation.
  6. Articles, papers, or written scientific works of any form, based in whole or in part on the KNMI/ERA-40 Wave Atlas, will contain an acknowledgment concerning the extracted data.

If you accept these conditions please enter the information below for our records, and press Accept.
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Andreas Sterl