In-Situ data and protocols
Data access & policy
Data submission
Extract matchup
Data format
Version & history
ODESA Validation
ODESA processing
Download level1 matchups

   Welcome to MERMAID, the MEris MAtchup In-situ Database


The MERMAID project aims at making available an easy-to-use centralised database of merged in-situ optical measurements with concurrent MERIS acquisitions to Ocean Colour researchers involved in the MERIS mission.

The long-term objectives of this database are to:
  • Enable the assessment of the MERIS marine Level 2 products delivered by the ENVISAT ground segment.
  • Support the monitoring of these MERIS products over the lifetime of the mission by providing a complete temporal coverage of the mission.
  • Provide support to atmospheric correction research.
  • Support vicarious adjustment of the MERIS instrument.
  • Provide a centralised validation resource to the ESA Optical Data Processor ODESA.


The database provides text files of in situ data, matched with concurrent and comparable MERIS L2 products (including flags, auxiliary information and the intermediate outputs of the processing). The extraction interface allows the users to select matchups according to their own requirements for site, parameters, flags and statistical screening, and produces validation statistics and plots.


Read the data access and policy to request an access to the MERMAID facility.

Contributing PIs get access to the full dataset, extraction facilities and validation tools.

More information about the project can be found in the 2nd MERIS/(A)ATSR User Workshop Proceedings (PDF).