NOAA/AOML is implementing quality control (QC) procedures in real-time and delayed-time mode for thermosalinograph (TSG) observations, based on the ten GOSUD (Global Ocean Surface Underway Data Pilot Project) real-time control tests. The real-time QC procedure has been implemented for the ships of the NOAA fleet and the Ship Of Opportunity Program (SOOP) while some steps of the delayed-time procedure are under development.

The figure below represent a summary of the QC steps implemented at NOAA/AOML and the general TSG data flow.

Quality control procedures in real-time mode

All the TSG data received by NOAA/AOML in real-time undergo a series of QC tests to ensure that only data of good quality are stored and distributed. The most important QC steps in our real-time procedure are:

1. Date.
2. Location.
3. Global sea surface salinity and temperature ranges.
4. Regional sea surface salinity and temperature ranges.
5. Detection of spikes along the ship track.
6. Gradient.
7. Constant value.
8. Climatology.

Only TSG data that have been approved by all these QC tests is encode in TRACKOB format and sent to the Global Telecommunication System (GTS). These procedures were implemented for the data from the ships of the NOAA fleet and the SOOP so that the quality controlled data is submitted to the GTS with a maximum delay that is typically less than 24 hours.

Quality control procedures in delayed-time mode

The TSG data is also processed in delayed-time mode by similar QC test that those described previously. A dditionally, we also conduct several more QC steps in delayed-time by comparing the TSG observations against:

• NCEP weekly analysis.
• Sea surface salinity and temperature observations from profiling floats, EXpendable Bathythermographs (XBTs), CTDs, and thermistor chains, obtained from NOAA/AOML data bases.

Water samples are regularly collected in selected transect and used to calibrate TSG measurements.

For more details on our QC procedures, please refer to the QC procedures sheet.