The sechhi disk data contains the following data columns:
Site: Name of the Scottish Coastal Observatory site where data were recorded
Date: Date of recording (yyyy-mm-dd)
Parameter: Secchi in all instances
Units: Measuring uints (meters in 0.5m steps for this sampling method)
Values: The recorded value
QF: Data quality flag value
Please note that all data are included and quality flagged. It is strongly recommended to read this documentation and consider which data will be appropriate for use, based on quality flags!
Data quality are based on the SeaDatanet Measurand qualifier flags vocabulary (L20) See http://vocab.nerc.ac.uk/collection/L20/current/
Some codes were replaced with numeric fields and the translation for specific vocabulary term codes are as follows
QF 0 = SDN:L20::0 - No quality control (http://vocab.nerc.ac.uk/collection/L20/current/0/)
QF 1 = SDN:L20::1 - Good value (http://vocab.nerc.ac.uk/collection/L20/current/1/)
QF 2 = SDN:L20::2 - Probably good value (http://vocab.nerc.ac.uk/collection/L20/current/2/)
QF 3 = SDN:L20::3 - Probably bad value (http://vocab.nerc.ac.uk/collection/L20/current/3/)
QF 4 = SDN:L20::4 - Bad value (http://vocab.nerc.ac.uk/collection/L20/current/4/)
QF 5 = SDN:L20::5 - Changed value (http://vocab.nerc.ac.uk/collection/L20/current/5/)
QF 6 = SDN:L20::Q - Below limit of detection (http://vocab.nerc.ac.uk/collection/L20/current/Q/)
QF 7 = SDN:L20::7 - Above limit of detection (http://vocab.nerc.ac.uk/collection/L20/current/7/)
QF 8 = SDN:L20::8 - Estimated or interpolated (http://vocab.nerc.ac.uk/collection/L20/current/8/)
QF 9 = SDN:L20::9 - Missing value ( http://vocab.nerc.ac.uk/collection/L20/current/9/)
QF 10 = SDN:L20::A - Data phenomenon uncertain (http://vocab.nerc.ac.uk/collection/L20/current/A/)
Recommendations for data use:
- Data flagged with QF 0 can be used but the user should note that it is not a finalised datapoint and could be edited in future datasets
- Data flagged with QF 1,2,5 and 8 can be used with confidence.
- It is recommended that data with flags QF 3 and QF 4 be rejected entirely.
- Data flagged with QF 6,7 - special consideration needs to be given as to how this data is treated.
- Data flagged with QF 9 - needs to be removed or ignored in any analysis.
- Data flagged with QF 10 should be treated with caution, and with the decision based on the parameter of interest and the use being made with it.