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Argo Real-time Quality Control Process

Argo Real-time Quality Control Process. 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 DACs. PROVIDE TO THE INTERNATIONAL OPERATIONAL AND RESEARCH

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Argo Real-time Quality Control Process

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  1. Argo Real-time Quality Control Process NOAA/AOML: Y.-H. DANESHZADEH, R. MOLINARI, R. SABINA, C. SCHMID CIMAS/UM: E. FORTEZA, X. XIA, H. YANG

  2. Guiding Philosophy of the international real-time DACs • PROVIDE TO THE INTERNATIONAL OPERATIONAL AND RESEARCH • OCEANIC COMMUNITIES PROFILES OF TEMPERATURE AND SALINITY • RESULTING 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

  3. Number of profiles quality controlled per year

  4. Atlantic Data Coverage Positions of the floats that have delivered data within the last 30 days

  5. How an Argo float works

  6. Data flow

  7. Real-time processing system

  8. Delayed-mode processing system

  9. Delayed-mode processing system

  10. Automatic quality control • Platform Identification • Impossible Date (valid & not before 1997) • Impossible Location (-180 to 180, -90 to 90) • Position on Land (ETOPO5) • Impossible Speed (<=3m/s) • Global Range (-2.5 to 40C, 0 to 41 psu) • Regional Range (Red Sea, Mediterranean Sea) • Pressure Increasing • Spike (| V2 - (V3 + V1)/2 | - | (V3 - V1) / 2 ) Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm

  11. Regional Range tests, definitions Red Sea · Temperature in range 21.7 to 40.0oC · Salinity in range 0.0 to 41.0 Mediterranean Sea · Temperature in range 10.0 to 40oC · Salinity in range 0.0 to 40.0

  12. temperature salinity Multiple-value spikes can be a problem. temperature level Spike test examples

  13. Automatic quality control • Top and Bottom Spike (no top spike test, bottom spike test currently under development) • Gradient (| V2 - (V3 + V1)/2 |) • Digit Rollover test (part of decoders) • Stuck Value (e.g. all values of T the same) • Density Inversion (gradient must be >=0) • Grey List (decided by PI & Operator) • Gross Salinity or Temperature Sensor Drift Test (checks if values in the deep ocean change too much, dT >1oC, dS >0.5 psu) Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm

  14. Bottom spike examples Currently no test is available to detect this problem.

  15. Gradient test examples If spikes are not excluded prior to application, then the test may flag some good points as bad. salinity level salinity level

  16. Density inversion test examples Current version: top to bottom. Flags wrong point because of three bad values around a good one.

  17. Density inversion test examples New version: top to bottom and bottom to top. One flag at wrong point because of three bad values around a good one.

  18. Automatic quality control • Visual QC: at AOML currently triggered by failure of any of the other tests on the profile data (except for grey list test). Additionally triggered by climatology/reanalysis test. • Frozen profile (>=5 almost identical consecutive profiles). • Deepest pressure test: pressure may not exceed nominal profile pressure given in the meta file by more than 10%. Documents are at http://www.ifremer.fr/coriolis/cdc/argo_rfc.htm

  19. Visual 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. temperature level salinity level

  20. pressure pressure Profile number Results of frozen profile test Blue circles indicate that T (top) or S (bottom) failed the test.

  21. Quality control statistics

  22. Quality control statistics

  23. US Argo DAC web page at AOML http://www.aoml.noaa.gov/phod/ARGO/HomePage

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