Data Quality Control
NODC Data Quality Control follows procedures implemented within the pan-European Infrastructure for ocean and marine data management - SeaDataNet (https://www.seadatanet.org/), which involves most European oceanographic data centres.
The overall approach consists in:
- Check of completeness of information and detection of missing mandatory metadata
- Check of date and location which includes detecting duplicates
- Detection of outliers (spikes, out of scale data, vertical instabilities, excessive gradients, etc)
- Check of increasing depth/pressure in vertical profiles
- Coherence with pre-existing climatologies available for a set of variables (Levitus 1998, 1° x 1° monthly climatology for biogeochemical parameters and MODB Mediterranean Climatology, Brasseur et al., 1996, for physical parameters)
As a result of metadata and data Quality Control, quality flags are assigned to metadata and data, according to a standard and harmonized Quality Flag Scale: https://vocab.seadatanet.org/v_bodc_vocab_v2/search.asp?lib=L20
Detailed information on Quality Check steps and useful references are available on:
MATER Data Manual, Vol. 1, Data management structure inventories format and codes. Quality Assurance. V3, 2001
Brasseur, P., Beckers, J. M., Brankart, J. M., & Schoenauen, R. (1996). Seasonal temperature and salinity fields in the Mediterranean Sea: Climatological analyses of a historical data set. Deep Sea Research Part I: Oceanographic Research Papers, 43(2), 159-192.