Transcript Quality Check Procedure at IFREMER

SISMER
Systèmes d’Informations Scientifiques pour la Mer
F-NODC
Quality Control Procedure
at IFREMER
Argo data management meeting
Brest 03-05/10/2000
TMSI/IDM/SISMER
Sept 2000
Quality Checks : Automatic + Visual
QC0 : Format, Codes, Completeness of Information
QC1 : Date, Time, Location, Duplicates
QC2 : Data Points
Result : Elimination or Quality Flag from GTSPP Scale
1
0
No QC
2
Correct Inconsistent
3
Doubtful
4
5
9
Bad
Changed
Missing
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
2
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)
3
QC1 Control of the location and Date
- Data collected in station
Automatic Checks
Results - Flag
Duplicate data sets
Elimination
Elimination or 5
Elimination or 5
Elimination or 5
Elimination or 3
Date
Ship/Platform velocity
Location/shoreline
Bottom sounding (ETOPO5)
5 = Correction/Interpolation
3 = doubtfull depth
4
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
5
QC2 - Control of the Data points
Minimum & Maximum - Broad Range Check
0
200
2000
6000
6
QC2 - Control of the Data points
Regional Adjustment for Broad Range Checks
7
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
8
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
9
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
10
Visual Checks

Check of the Internal Coherence



Check of the External Coherence



QC1 : Check of the route or trajectory
QC2 : Internal coherence of the values and search for shifts or
gaps
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)
11
QC1 Control of the location and Date
VISUAL CHECKS - Data collected in station
12
QC1: Control of the location and Date
- Time series on fixed mooring
13
QC2 - Control of the Data points
Visual Checks
14
QC2 - Control of the Data points
Visual Checks - case of problematic climatology
15