Organisation

Validation Strategy

The time schedule of validation can be roughly split up in four phases:

1. The Rehearsal Phase:
   Testing of all procedures. (starting 3 months before launch, lasting 6 month)
2. The Commissioning Phase:
   After instrument calibration has taken place, validation measurements are required to make sure that the results retrieved from OMI measurements are believable, and more or less correct. (starting 3 months after launch, lasting 6 months)
3. The Core Phase:
   Normally lasting about a year, during which every single product is validated to the level of accuracy, precision, and coverage stated in the science requirements. (starting 3 months after launch, lasting 12 month)
4. Long-term Phase:
   Lasting throughout the mission, to assure that the retrieved products are still valid to the stated accuracies, independent of changes in the instrument and/or the spacecraft. (starting 15 months after launch)

Reference data for validation is to be preferably obtained from different sources, i.e. in situ measurements from balloons or aircraft, ground-based measurements from remote sensing and in-situ systems and measurements from other satellite instruments, and by applying different measurement techniques.

Although very much state of the art and at the frontier of academic science, retrieval algorithms for atmospheric trace gases, clouds and aerosols can always be improved. Fortunately, with OMI have at least two algorithms available for each of our data products as the international OMI project is a very successful merger of the American and European atmospheric science communities. By using the CAMA tool the outcome of these retrieval algorithms can be compared where each and every ground pixel is used. With CAMA many algorithmic features have been comprehensively explored at an early stage of the data production that otherwise have taken years to analyze with reference data.

At the moment we are well into the long term validation phase of OMI. Most data products have been accurately validated and many publications can be found on this website and on the Aura Aura Publication Overview page.