Why quality control?

When measurements reach our database, they may contain errors, which may be due to sensor drift, a problem when decoding the data or some other issue. To comply with international standards and in accordance with large international programmes, SISMER therefore carries out quality control, which will include automatic/objective checks and visual/subjective checks.

The aim of this quality control process is to enhance the reliability of data delivered to users, but also to allow exchanges of consistent and comparable data at European and international levels. 
Each dataset of vertical profiles or time series undergoes a series of automatic checks. These automatic checks result in a quality indicator assigned to each numerical value in the data files.

Several levels of control

Depending on the type of data processed, the level of control will be different. From the most rudimentary to the most advanced, several levels of control are listed below according to the type of data:

  1. Vessel data: data control is limited to checking the coherence of time references (acquisition dates) and spatial references (positions) for data provided by GENAVIR.
  2. Physics and chemistry data: The data are checked automatically and visually and a quality indicator is assigned to each item of data and metadata.
  3. Operational oceanography data: Objective analyses are carried out on sets of data and then the data are re-checked (automatic and visual check), but here, the data are corrected in a new field (corrected value).
  4. Satellite data: the level of processing is the highest because reprocessing is performed on the datasets.