CTD

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This page provides information on the requirements for submitting, archiving and publishing Conductivity, Temperature, Depth sonde (CTD) data to ensure fulfilling the FAIR data principles.

PANGAEA differentiates between raw data and processed data publications. The differences are explained below. Please note the extra paragraph on *.cnv files.

If you are preparing CTD data in the context of the DAM Underway Research Data project, find specific project related details on this page: CTD Underway data.

Standardized meta information

The following information needs to be included in any data submission at PANGAEA. To start a data submission at PANGAEA go to https://www.pangaea.de/submit/ . Further information on the ticket system used for communication and documentation during the processing of the data submission can be found in this wiki.

Workflow: Processing of a Data Submission

List of authors

Usually, the list of authors should contain the scientist responsible for the sampling device, the chief scientist and the PI, the contact person responsible for the data.

Dataset title

The title should ideally reflect what has been measured, observed, or calculated, when, where, and how. If applicable, the title of the data publication should be generalized and is defined by the specific [ship], [cruise] and [device].

Abstract

In general, a generalized abstract is mandatory to each dataset regarding [ship], [cruise] and certain peculiarities. For more information on what needs to be included in a PANGAEA data publication abstract see this page.

References

Several references may be of importance for the dataset.

Cruise report

If a cruise report is available it is sometimes already archived at the Technische Informationsbibliothek and might be linked to the dataset (see this example).

Data processing report

If a data processing report exists, it contains information on processing and quality control procedures. It enables to reproduce the processed data from raw data. The preferred format for submission is pdf (see this example).

Currently, the data processing reports are being archived at PANGAEA; A long-term solution will include the assignment of a doi for each data processing report.

Linking between processed and raw data

If possible, the raw data should be linked to the processed dataset and vice versa. This link may lead to an external source, but it may also be an PANGAEA-internal link (see this example ).

Additional data files

These may, for example, include additional *.cnv files in zip format, protocol files in pdf format, salinity measurements as .txt files, etc. They will be stored on one of PANGAEA's servers and can be accessed via a link to the data publication (see this example).

Further information

Cruise label

The [cruise] label usually includes [ship]number/leg (e.g.: MSM88/1). Please provide further information on the cruise (synonyms: campaign, expedition, leg) as described in https://wiki.pangaea.de/wiki/Campaign. You may also check the overview table of campaigns and the existing labels.

Event label(s)

The event label(s) should be part of each data submission. Event labels equal the station labels and provide meta-information for the data. An Event Label consists of the cruise label and the station ending: [ship]number/leg_station (e.g.: HE605_1-1).

Device/Sensor

Information on the device used for measuring should also be provided, so it can be linked to the measured parameters (see this example).

Processed Data

Processed data are prepared for submission following the Authors Guides, which includes

  • date and time information in ISO format (e.g. 1954-04-07T13:34:11) in coordinated universal time (UTC)
  • 3 dimensional geocode: latitude/longitude in decimal degree (WGS84) and water depth of CTD
  • an event for each CTD cast
  • full parameter names (no abbreviations) including units
  • standardized meta information (see above).

Examples of a processed CTD data publication

Physical oceanography during RV HEINCKE cruise HE609: https://doi.pangaea.de/10.1594/PANGAEA.961721.

Physical Oceanography measured with CTD on Triaxus topAWI (towed ocean profiler of the AWI) during MERIAN cruise MSM93: https://doi.pangaea.de/10.1594/PANGAEA.940010.

File name

If CTD profiles are provided as individual data files, please name them after their events (see the Event label(s) paragraph above).

File formats

Possible file formats include .txt, .tab, .csv, .xlsx . The preferred file format is tab-delimited text file. The encoding is preferably UTF-8.

Layout

Please do not include any header except column names. The decimal separator should be "." and the number of decimals should always reflect the measurement precision. Not available numbers are displayed as blanks in PANGAEA. Preferably, the submitted data contains blanks. Alternatives such as "NaN", "NA" are acceptable in the data table.

Parameters and meta data information in the data table (example)

This table gives an overview on the parameter names and specifications as they will appear on the web and in the download file of the data. If possible, these names should be included in the submission data table. Also the format and unit of data should be submitted as displayed here. The methods will be included in the data publication by the data editor as specified in the submitted meta-information.

Parameter Name Format Unit Value Principal Investigator Method/Device Comment
Event label HE609_1-10
DATE/TIME yyyy-MM-ddTHH:mm:ss 2022-10-05T10:23:55
LATITUDE decimal 53.7504
LONGITUDE decimal 8.0703
Depth, water m 18.2 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; calculated using SBE Data Processing Version 7.22.5
Pressure, water dbar 18.4 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus
Temperature, water °C 14.5508 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus ITS-90; in situ
Conductivity mS/cm 39.2215 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; measured with Conductivity sensor, Sea-Bird, SBE 4
Salinity 32.0127 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; calculated using SBE Data Processing Version 7.22.5 PSU
Temperature, water, potential °C 14.5482 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; calculated using SBE Data Processing Version 7.22.5 and SEAWATER Routines ITS-90
Density, sigma-theta (0) kg/m3 23.7659 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; calculated using SBE Data Processing Version 7.22.5 and SEAWATER Routines
Oxygen µmol/l 236.233 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; Calculation according to Morgan (1994; SEAWATER Routines)
Oxygen saturation % 90.48 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; calculated using SBE Data Processing Version 7.22.5 and SEAWATER Routines
Attenuation, optical beam transmission % 20.02 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; measured with Transmissometer, WET Labs, C-Star
Chlorophyll a µg/l 2.81 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus; measured with Fluorometer, WET Labs, ECO-AFL
Number of observations # 4 Tippenhauer, Sandra CTD, Sea-Bird, SBE 911plus

Note: If Quality Flags are used, the flagging code needs to be explained and will be archived in the parameter comment.

Templates for processed CTD data submissions

These templates may help for preparation of your data file:

  • template in excel format; Additional meta information as name of the principal investigator and name of method and device are either given as comments during the submission process or via an additional sheet in the excel file.


A few information on density in water:

Density = 1027.1234 kg/m³

Sigma = Density - 1000 = 27.1234 kg/m³

Density depends on pressure, temperature and salt content: Density = f(P,T,S)

As a rule, one considers the density (or sigma) and sets P = 0 and denotes this as sigma-theta.

If the potential temperature (theta) is used instead of the in-situ temperature T, then the result is the potential density or sigma-theta.

Density in situ ( Note: "Density, mass density [kg/m³]" in 4D) - should always have values around 1000 (e.g. 1027)

Density, potential [kg/m³] should also always have values around 1000 (e.g. 1027)

Density sigma-theta [kg/m³] should always have lower tens values, e.g. around 27

Density, sigma, in situ [kg/m³] should also have lower tens values, e.g. around 27

Further information on parameters: https://wiki.pangaea.de/wiki/Parameter.

Raw Data

CTDs produce several raw files in various formats. The output of raw data varies depending on the preferences set by the CTD user.

A minimum set of the following files for each cast are needed for a raw data publication:

  • bottle information file *.bl
  • sensor configuration including calibration information file *.xmlcon
  • header file containing meta data on CTD system, position and time *.hdr
  • CTD raw data in hexadecimal format file *.hex

Optional additional files:

  • bottle data *.btl
  • summary file in text format *.cnv
  • protocol sheet/file *.pdf

Example of a CTD raw data publication

Raw data of physical oceanography during RV POLARSTERN cruises PS130/1 and PS130/2. https://doi.pangaea.de/10.1594/PANGAEA.957843.

File name

Please name each individual data file after its event (see the Event label(s) paragraph above).

The special case of *cnv files

Some CTDs provide *cnv files consisting of a meta data summary plus raw data translated to text format which might include flagging. This data type is neither considered raw data nor processed data. Please see a detailed description on raw and processed data in the paragraphs above.

If you like to archive *.cnv files along with either raw or processed data submissions, you can do so as additional optional files. These will be either listed together with other raw data files or linked as a zipped additional file.

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