Data Formats & QC

Data Formats

OGS-NODC is a partner of SeaDataNet network, the robust and state-of-the-art pan-European infrastructure for providing open access to up-to-date and high quality marine metadata, data and data products. It implies that all available data are formatted with common data transport formats, which interact with other SeaDataNet standards (Vocabularies, Quality Flag Scale) and SeaDataNet analysis & visualization tools, that is, Ocean Data View (ODV) and Data-Interpolating Variational Analysis (DIVA). Therefore the following data transport formats are implemented for profiles and time series:

• SeaDataNet ODV4 (ASCII);
• SeaDataNet NetCDF (binary);
• SeaDataNet MedAtlas as optional extra format.

Examples and the Data Transport Formats manual can be found at SeaDataNet web site.

Data Quality Control

NODC Data Quality Control follows procedures implemented within SeaDataNet, 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.

Detailed information on Quality Check steps and useful references are available on:
SeaDataNet Data quality control procedures, V 2.0, 2010
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.
Maillard, C., Fichaut, M., & Dooley, H. (2001). MEDAR-MEDATLAS Protocol. Part I. Exchange format and quality checks for observed profiles. Ifremer Rep. R. INT. TMSI/IDM/SISMER/SIS00–084.