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

6

QC2 - Control of the Data pointsMinimum & Maximum - Broad Range Check

0

200

2000

6000

7

QC2 - Control of the Data pointsRegional Adjustment for Broad Range Checks

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)

12

QC1 Control of the location and Date VISUAL CHECKS - Data collected in station

13

QC1: Control of the location and Date - Time series on fixed mooring

14

QC2 - Control of the Data pointsVisual Checks

15

QC2 - Control of the Data pointsVisual Checks - case of problematic climatology