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Argo Real-time Quality Control Argo Real-time Quality Control ProcessProcess
NOAA/AOML: Y.-H. DANESHZADEH,R. MOLINARI, R. SABINA, C. SCHMID
CIMAS/UM: E. FORTEZA, X. XIA, H. YANG
Guiding Philosophy of the international real-time DACsGuiding Philosophy of the international real-time DACs
PROVIDE TO THE INTERNATIONAL OPERATIONAL AND RESEARCHOCEANIC COMMUNITIES PROFILES OF TEMPERATURE AND SALINITYRESULTING FROM ARGO FLOATS THAT MEET THE FOLLOWING CRITERIA:
DATA HAVE BEEN MANAGED IN A UNIFORM MANNER
DATA ARE FREE
DATA ARE READILY ACCESSIBLE
DATA ARE AVAILABLE WITHIN A TIMELY MANNER
DATA HAVE BEEN QUALITY CONTROLLED TO REMOVE THE MOST EGREGIOUS ERRORS
COST OF REAL TIME QUALITY CONTROL IS REASONABLE
Number of profiles quality controlled per yearNumber of profiles quality controlled per year
Positions of the floats that have delivered data within the last 30 days
Atlantic Data Atlantic Data CoverageCoverage
How an Argo float works
Data flowData flow
Real-time Real-time processing processing
systemsystem
Delayed-mode processing systemDelayed-mode processing system
Delayed-mode processing systemDelayed-mode processing system
Automatic quality controlAutomatic quality control
1.1. Platform IdentificationPlatform Identification
2.2. Impossible Date (valid & not before 1997)Impossible Date (valid & not before 1997)
3.3. Impossible Location (-180 to 180, -90 to 90)Impossible Location (-180 to 180, -90 to 90)
4.4. Position on Land (ETOPO5)Position on Land (ETOPO5)
5.5. Impossible Speed (<=3m/s)Impossible Speed (<=3m/s)
6.6. Global Range (-2.5 to 40C, 0 to 41 psu)Global Range (-2.5 to 40C, 0 to 41 psu)
7.7. Regional Range (Red Sea, Mediterranean Sea)Regional Range (Red Sea, Mediterranean Sea)
8.8. Pressure IncreasingPressure Increasing
9.9. Spike (| V2 - (V3 + V1)/2 | - | (V3 - V1) / 2 )Spike (| V2 - (V3 + V1)/2 | - | (V3 - V1) / 2 )
Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm
Regional Range tests, definitionsRegional Range tests, definitions
Red SeaTemperature in range
21.7 to 40.0oCSalinity in range
0.0 to 41.0
Mediterranean SeaTemperature in range
10.0 to 40oCSalinity in range
0.0 to 40.0
tem
pera
ture
Spike test examplesSpike test examples
Multiple-value spikes can be a problem.
level
tem
pera
ture
sali
nity
Automatic quality controlAutomatic quality control
10.10. Top and Bottom Spike (no top spike test, bottom Top and Bottom Spike (no top spike test, bottom spike test currently under development)spike test currently under development)
11.11. Gradient (| V2 - (V3 + V1)/2 |)Gradient (| V2 - (V3 + V1)/2 |)12.12. Digit Rollover test (part of decoders)Digit Rollover test (part of decoders)13.13. Stuck Value (e.g. all values of T the same)Stuck Value (e.g. all values of T the same)14.14. Density Inversion (gradient must be >=0)Density Inversion (gradient must be >=0)15.15. Grey List (decided by PI & Operator)Grey List (decided by PI & Operator)16.16. Gross Salinity or Temperature Sensor Drift Test Gross Salinity or Temperature Sensor Drift Test
(checks if values in the deep ocean change too (checks if values in the deep ocean change too much, dT >1much, dT >1ooC, dS >0.5 psu)C, dS >0.5 psu)
Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm
Bottom spike examplesBottom spike examples
Currently no test is available to detect this problem.
Gradient test examplesGradient test examples
If spikes are not excluded prior to application, then the test may flag some good points as bad.sa
lini
ty
sali
nity
level
level
Density inversion test examplesDensity inversion test examples
Flags wrong point because of three bad values around a good one.
Current version: top to bottom.
Density inversion test examplesDensity inversion test examples
One flag at wrong point because of three bad values around a good one.
New version: top to bottom and bottom to top.
Automatic quality controlAutomatic quality control
17.17. Visual QC: at AOML currently triggered by Visual QC: at AOML currently triggered by failure of any of the other tests on the profile data failure of any of the other tests on the profile data (except for grey list test). Additionally triggered (except for grey list test). Additionally triggered by climatology/reanalysis test.by climatology/reanalysis test.
18.18. Frozen profile (>=5 almost identical consecutive Frozen profile (>=5 almost identical consecutive profiles).profiles).
19.19. Deepest pressure test: pressure may not exceed Deepest pressure test: pressure may not exceed nominal profile pressure given in the meta file by nominal profile pressure given in the meta file by more than 10%.more than 10%.
Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm
Visual quality controlVisual quality control
Two cases of bad profiles that can not be detected by the standard Argo QC tests. For these a climatology test that triggers a visual QC can be very helpful.
level
level
tem
pera
ture
sali
nity
Blue circles indicate that T (top) or S (bottom) failed the test.
Results of frozen profile test
Profile number
pres
sure
pres
sure
Quality control statisticsQuality control statistics
Quality control statisticsQuality control statistics
http://www.aoml.noaa.gov/phod/ARGO/HomePage
US Argo DAC web page at AOML