All of the files in this database have been reviewed and subjected to quality control procedures, after which, data is called the Best Basic Version (BBV). The BBV data are in standard scientific units, have been reviewed by the database manager, and are intended as the starting point for scientific analysis. The individual records are not flagged with data quality words, but inclusion in the database implies the measurements passed all the validation tests.

This database is intended to be useful without requiring detailed knowledge of the particular sensors, loggers, platforms, or field activities that produced the data. Users are encouraged to consult the applicable data reports (see Appendix 3), when available, if detailed information about the instrument configuration is needed.

The BBV is processed to the following standards:

• Data are calibrated and expressed in standard scientific units.
• Time base has been verified.
• Calibration parameters have been verified.
• Clearly erroneous data values have been removed and replaced with interpolations or pad values (typically 1e35).
• Data recorded out-of-water or off-location have been removed.
• Appropriate and correct metadata are attached.
• Data sets are NetCDF files that conform to the EPIC conventions.