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

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Spike test examplesSpike test examples

Multiple-value spikes can be a problem.

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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

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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.

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Blue circles indicate that T (top) or S (bottom) failed the test.

Results of frozen profile test

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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