Guide to CTD data submission

Please also read the general guide to data submission.

Data standard

Data may be supplied as one file per CTD station or all CTD stations from a cruise in one file. Down cast data (if available) should always be present. If water samples have been collected, the discrete up cast value (measured at the time of the water sample) should be provided.

Data should be checked for quality and pre-edited or flagged for erroneous values. All relevant calibrations, laboratory and field, should be applied to the data. Discrete water samples collected for the purposes of calibration may also be submitted to the Data Assembly Centre (GDAC).

It is recommended that data set header information be included within the data file. However, if this is not possible, sufficient indexing must be provided to link the information to the data values. Copies of the original CTD log sheets should also be supplied with the data.

To ease ingestion, it would be helpful to include a standardised data definition statement within the file header or adopt a uniform file format for all CTD stations from one cruise. If homogeneity is not possible, please document the changes in the file format and supply with the data.

Metadata specific to CTD data

Collection details

Ship and cruise identifier.
Project (if applicable).
CTD station identifier.
Date/time of the start of the measurement.
Position and method of position fix (i.e. DGPS, GPS).
Water column depth (specify method — i.e. sounding and methodology, chart).
Water sample references — collected for calibration purposes.

Instrument details

Instrument description, reference number, manufacturer and model — provide a literature reference, web site reference or brief description. Include; accuracy, resolution and response range of individual sensors.

Sample data — for calibration purposes

A description of or reference to full laboratory methods and procedures.
Details of any external sample analysis, including the laboratory name and accreditation level.
A description of or reference to any internal or external quality assurance procedures.

Calibrations

Laboratory calibration coefficients.
Field calibration coefficients (i.e. water samples).

Data sampling/processing

Filtering, de-spiking or smoothing methods.
Editing and quality control methods.
Quality control report.