Marine Data Quality Flags:

Quality Flag Tables

In all these systems, "QC" refers to quality control procedures.

Argo

• 0 - No QC was performed
• 1 - Good data
• 2 - Probably good data
• 3 - Probably bad data that are potentially correctable
• 4 - Bad data
• 5 - Value changed
• 8 - Interpolated value
• 9 - Missing value

British Oceanographic Data Centre (BODC)

• Field left blank - Acceptable value
• < - Below detection limit
• > - In excess of quoted value
• A - Taxonomic flag for affinis (aff.)
• B - Beginning of CTD down/up cast
• C - Taxonomic flag for confer (cf.)
• D - Thermometric depth
• E - End of CTD down/up cast
• H - Extrapolated value
• I - Taxonomic flag for single species (sp.)
• K - Improbable value, unknown quality control source
• L - Improbable value, originator's quality control
• M - Improbably value, BODC quality control
• N - Null value

European Sea Level Service (ESEAS)

• 0 - No quality control
• 1 - Correct value
• 2 - Interpolated value
• 3 - Doubtful value
• 4 - Isolated spike or wrong value
• 5 - Correct but extreme value
• 6 - Reference change detected
• 7 - Constant values for more than a defined time interval
• 8 - Out of range
• 9 - Missing value

Global Temperature and Salinity Profile Program (GTSPP)

• 0 - No QC was performed
• 1 - QC was performed; good data
• 2 - QC was performed; probably good data
• 3 - QC was performed; probably bad data
• 4 - QC was performed; bad data
• 5 - The value was changed as a result of QC
• 9 - The value is missing

Ocean Data View Software

• 0 - Good quality
• 1 - Unknown quality
• 4 - Questionable quality
• 8 - Bad quality

PANGAEA

• Left blank - Valid
• ? - Questionable
• / - Not valid
• * - Unknown
• # - Individual definition
• > - Larger than
• < - Less than

Quality Assurance of Real-Time Oceanographic Data (QARTOD)

• 0 - Quality not evaluated
• 1 - Bad
• 2 - Questionable/suspect
• 3 - Good
• 9 - Missing data

SeaDataNet

• 0 - No quality control
• 1 - Good value
• 2 - Probably good value
• 3 - Probably bad value
• 4 - Bad value
• 5 - Changed value
• 6 - Value below detection
• 7 - Value in excess
• 8 - Interpolated value
• 9 - Missing value
• A -Value phenomenon uncertain

Swedish Meteorological and Hydrological Institute (SMHI)

• Left blank - Good value
• ! - Extreme/suspicious value, checked manually and compared with other relevant parameters and found correct
• ? - Questionable value
• B - Bad value
• < - Below detection limit/less than
• > - Above detection limit/greater than
• | - Manually interpolated/extrapolated
• C - Value from CTD temp/salin/fluor/oxyg
• Z - Zero by definition

WOCE CTD

• 1 - Not calibrated
• 2 - Acceptable measurement
• 3 - Questionable measurement
• 4 - Bad Measurement
• 5 - Not reported
• 6 - Interpolated over >2 dbar level
• 7 - Despiked
• 9 - Not sampled

WOCE Bottle Samples

• 1 - Sample for this measurement was drawn from water bottle but not received
• 2 - Acceptable measurement
• 3 - Questionable measurement
• 4 - Bad Measurement
• 5 - Not reported
• 6 - Mean of replicate measurements
• 7 - Manual chromatographic peak measurement
• 8 - Irregular digital chromatographic peak integration
• 9 - Sample not drawn for this measurement from this bottle

World Ocean Database (Individual Observed Parameters)

• 0 - Accepted value
• 1 - Range outlier (outside of broad range check)
• 2 - Failed inversion check
• 3 - Failed gradient check
• 4 - Failed observed level "bull's-eye" check or zero-gradient check
  • This revised wording confirmed with the US NODC OCL, 2009-07-13
• 5 - Failed combined gradient and inversion checks
  • This revised wording confirmed with the US NODC OCL, 2009-07-13
• 6 - Failed range and inversion checks
• 7 - Failed range and gradient checks
• 8 - Failed range and questionable data checks
• 9 - Failed range and combined gradient and inversion checks

World Ocean Database (Depths)

• 0 - Accepted value
• 1 - Duplicates or inversions in recorded depth (same or less than previous depth)
• 2 - Density inversion

World Ocean Database (Entire Stations)

• 0 - Accepted station
• 1 - Failed annual standard deviation check
• 2 - Two or more density inversions (Levitus, 1982 criteria)
• 3 - Flagged cruise
• 4 - Failed seasonal standard deviation check
• 5 - Failed monthly standard deviation check
• 6 - Failed annual and seasonal standard deviation check
• 7 - Bull's-eye from standard level data or failed annual and monthly standard deviation check
• 8 - Failed seasonal and monthly standard deviation check
• 9 - Failed annual, seasonal, and monthly standard deviation check