TMSI/IDM/SISMER Sept 2000
SISMERSISMER Systèmes d’Informations Scientifiques pour la Mer
F-NODC
Quality Control Procedure at IFREMER
Argo data management meeting
Brest 03-05/10/2000
2
Quality Checks : Automatic + Visual
QC0 : Format, Codes, Completeness of Information
QC1 : Date, Time, Location, Duplicates
QC2 : Data PointsResult : Elimination or Quality Flag from GTSPP Scale
References UNESCO/COI/IODE : Manual of Quality Control Procedures for validation of
Oceanographic Data - Manuals and Guides 26 - (GTSPP chapter) ICES -GETADE Formatting Guidelines for Oceanographic Data Exchange
(http://www.ices.dk/ocean/) ICES -MDM QA Guidelines - CTD - Marine Data Management working Group (CIEM)
Reports UNESCO/IOC/IODE : GF3 A General Formatting System for Geo-Referenced Data -
Manual and Guides 17
0 1 2 3 4 5 9
No QC Correct Inconsistent Doubtful Bad Changed Missing
3
QC0 - FORMATS, CODES, INFORMATION
Check of Meta-Data/Information : RDBS - ORACLE
Present Input Format for full QC : autodescriptive ASCII (MEDATLAS) NetCDF (in preparation) Other input formats (Via conversion interfaces)
4
QC1 Control of the location and Date - Data collected in station
Automatic Checks Results - Flag
Duplicate data sets EliminationDate Elimination or 5
Ship/Platform velocity Elimination or 5
Location/shoreline Elimination or 5
Bottom sounding (ETOPO5) Elimination or 3
5 = Correction/Interpolation 3 = doubtfull depth
5
QC2 - Control of the Data points
Automatic Checks
Results/Flag Pressure record only Elimination
Out of the regional scale 4
(min & max values)
Non Increasing pressure 4
Data below the bottom depth 4
Coherence with pre-existing statistics
(LEVITUS, REYNAUD, MEDATLAS) 2
Constant profiles 4
Spikes - Gradient 3
Vertical instability > noise 4
8
QC2- Vertical Stability Check
Threshold noise for instability detection 0.03 in sigma-t for high resolution deep water
stations 0.05 to 0.1 for coastal or low resolution stations
4 data points to be checked : 2 levels T, S Automatic seach for further anomaly
if any flag=4 at this point if none flag=4 at the 4 points and manual
decision
9
QC2 - Spike and Gradient Checks
On 2 consecutive points at the top and bottom
On 3 consecutive points in between
Threshold for detection adjustable in geographical
subregions and vertical layers
10
QC2- Climatological Checks
Several available climatologies : Levitus 94, 98, Reynaud, Medatlas, MODB
Default Climatology is Levitus 98 1x1 degree Allowed Variability
Shallow water stations bottom < 100 m : 5 standard deviations
Shelf Stations 200< bottom < 400 : 4 standard deviations
Deep Stations bottom > 400 m : 3 standard deviations
11
Visual Checks
Check of the Internal Coherence QC1 : Check of the route or trajectory QC2 : Internal coherence of the values and search for shifts or
gaps Check of the External Coherence
QC1 : Display of all the profiles of another cruise/trajectory if at least one station is in the space/time vicinity
QC2 : Possibility of superposing the profiles made during another experiment in the same region
Removing Doubts Vertical intabilities Spikes Climatological test (Erroneous climatological standard deviations)