We have reviewed the HOT bottle salinity history through its instruments, methods, standardization, and quality control. The following list includes a summary of  suggestions to maintain and improve the data quality.

1. [Section 1.1.2] An evaporation correction of 1 mpsu/14 days should be applied to data obtained from samples in plastic bottles that were measured on or later than the 15th day after the cruise.

2. [Section 1.3.1] Each Autosal operator should keep their eyes open for signs of normal Autosal operation, such as flashing light bulbs, clean conductivity cell, smooth flow in and out, etc.

3. [Section 1.3] All regular maintenance must be documented in the Autosal Run Log. The Run Log binder should contains template sheets for the Run Log as well as the Salinity Measurement Sheets, which must be refilled and kept in stock when they run low. All repairs must be documented in the Run Log as well as in the Access 2000 Maintenance History Database.

4. [Section 2.1] Every Autosal operator must read the most current version of the Autosal Measurement and Salinity Data Processing Guide (Appendix K) before measuring any salinity samples.

5. [Section 2.1.1] Duplicate samples should always be drawn from the rosette in conjunction with primary samples when sampling out at sea. After each HOT cruise, salinity samples should not be left for more than a week before measuring.

6. [Section 2.1.2] Keeping constant bath and ambient temperatures when running salinity samples is crucial. The bath temperature must be noted if the thermometer shows anything other than 24o C. The ambient temperature must be maintained within 1-2o C of 21o C.

7. [Section 2.2.2] The person writing the Salinity Report must be meticulous in recording all corrections and unusual events in the report and to carefully double-check the report before filing it away into the Salinity Data Processing Reports binder.

8. [Section 2.3.2] All corrections applied to the salinity data must be consolidated in the written Salinity Measurement Report.

9. [Section 3.1.1] Standardization methods using IAPSO seawater must be consistent. The amount of standardization knob adjustment (if adjusted) and the associated conductivity readings must be written down in the measurement sheets. The standardization knob must NOT be adjusted after initial standardization. Furthermore, after initial standardization, two more IAPSO ampoules should be measured, one at the end of the measurement run and the other at the end of the duplicate session.

10. [Section 3.1.3] We should continue monitoring IAPSO within-batch differences to detect possible Autosal drift. The corrections to IAPSO bottles suggested by Aoyama et al. (2002, Appendix P) should be applied to the HOT samples.

11. [Section 3.2.1] We suggest looking closely at substandard batch mean data for cruises with large error bars (Figure 5B) to eliminate outliers before further analysis.

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