Frequently Asked Questions

1. Where can I learn more about the SOCAT data collection?
A series of publications documents the public SOCAT data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014 and 2016). A list of references is at the end of these FAQs.

2. What datasets are included in the SOCAT data collection?
The public SOCAT data collection has quality controlled surface ocean fCO₂ (fugacity of CO₂) values in a uniform format from the global oceans and coastal seas. Data coverage increased from the 1990s onwards.

3. How should I cite the SOCAT data products?
Version 2023: Bakker et al. (2016)
Version 2022: Bakker et al. (2016)
Version 2021: Bakker et al. (2016)
Version 2020: Bakker et al. (2016)
Version 2019: Bakker et al. (2016)
Version 6: Bakker et al. (2016)
Version 5: Bakker et al. (2016)
Version 4: Bakker et al. (2016)
Version 3: Bakker et al. (2016)
Version 2: Bakker et al. (2014)
Version 1 (synthesis data products): Pfeil et al. (2013)
Version 1 (gridded data product): Sabine et al. (2013) and Pfeil et al. (2013)

4. What are the agreed-upon SOCAT QC flags?
Each data set in SOCAT has been assigned a data set quality control flag (Pfeil et al., 2013; Bakker et al., 2014, 2016). Data sets with flags of A, B, C, D, or E are included in the public version 3. The synthesis and gridded files contain data sets with flags of A to D. Data sets with a flag of E are available in a separate synthesis file (Bakker et al., 2016).

WOCE flags are applied to all fCO₂ values in the collection. A WOCE flag of 2 means ‘good’, a WOCE flag of 3 means ‘questionable’, and a WOCE flag of 4 means ‘bad’. The synthesis and gridded files contain fCO₂ values with a WOCE flag of 2. fCO₂ values with WOCE flags of 3 and 4 can be accessed in the individual data set files and via the Data Set Viewer (Bakker et al., 2016).

5. How was fCO₂ computed for data sets that reported other CO₂ parameters?
The procedure by which the variable fCO2_rec (the recomputed fCO₂) was obtained is described in Pfeil et al. (2013) and Bakker et al. (2014, 2016). The variable fCO2rec_src, available in the SOCAT synthesis data product, contains an integer (1-14) that indicates which pathway was used for the calculation of each fCO2_rec value.

6. How can I get a quick overview of the SOCAT data collection?
The SOCAT Data Set Viewer and the Gridded Data Viewer provide interactive access to the SOCAT data collection. Data can be selected by e.g. year, region, vessel and season. Making maps and property-property plots is straightforward. Access is via the links on the different SOCAT version pages (e.g. for version 2022) under the Interactive header. More information on these Data Viewers follows below.

7. How can I download all or parts of the SOCAT data collection?
The data collection is available as downloadable individual data set files, as regional and global synthesis files and as gridded files. Use the links on the different SOCAT version pages (e.g. for version 2022) under the Data Files header.

Selections of data sets and gridded data can be downloaded via the SOCAT Data Set Viewer and the Gridded Data Viewer (see FAQ section below). Access is via the links on the different SOCAT version pages (e.g. for version 2022) under the Interactive header.

A variety of file formats is available for download. A full description of these data products is in Pfeil et al. (2013), Sabine et al. (2013) and Bakker et al. (2014, 2016).

8. How can I get the SOCAT data collection into Matlab?
Matlab code for reading the SOCAT synthesis files and gridded files is available via the different SOCAT version pages (e.g. for version 2022) under the Instructions and MATLAB scripts header under the Synthesis and Gridded Files from NOAA NCEI dropdown.

9. How can I access the SOCAT data collection in Ocean Data View (ODV)?
The SOCAT synthesis and gridded files are available in Ocean Data View via the ‘Download Data’ link on the SOCAT start page (https://www.socat.info).

10. What is the SOCAT Fair Data Use Statement?
The SOCAT Fair Data Use Statement is available here. In summary, we expect that users of SOCAT data products:

• Generously acknowledge the contribution of SOCAT data providers and investigators in the form of invitation to co-authorship, reference to relevant scientific articles by data providers or by naming data providers in the acknowledgements. Specifically, in regional studies invite large data providers, who frequently possess valuable expert knowledge on data and region, to collaborate at an early stage, which may lead to an invitation of co-authorship. We recognize that co-authorship is only justified in case of a significant scientific contribution to a publication and that provision of data on its own does not warrant co-authorship.
• Cite SOCAT and its data products as:
  Version 2023: Bakker et al. (2016)
  Version 2022: Bakker et al. (2016)
  Version 2021: Bakker et al. (2016)
  Version 2020: Bakker et al. (2016)
  Version 2019: Bakker et al. (2016)
  Version 6: Bakker et al. (2016)
  Version 5: Bakker et al. (2016)
  Version 4: Bakker et al. (2016)
  Version 3: Bakker et al. (2016)
  Version 2: Bakker et al. (2014)
  Version 1 (synthesis data products): Pfeil et al. (2013)
  Version 1 (gridded data product): Sabine et al. (2013) and Pfeil et al. (2013)
• Include in the acknowledgements:
  ‘The Surface Ocean CO₂ Atlas (SOCAT) is an international effort, endorsed by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS) and the Integrated Marine Biosphere Research (IMBeR) program, to deliver a uniformly quality-controlled surface ocean CO₂ database. The many researchers and funding agencies responsible for the collection of data and quality control are thanked for their contributions to SOCAT.’
• Report problems to submit@socat.info.
• Inform submit@socat.info of publications in which SOCAT is used.

11. How do I upload data to SOCAT
Information on how to upload data can be found in a video and document here. 

12. How do I quality control data
Information on how to quality control data can be found in a video and document here. 

For further advice please contact submit@socat.info.

Using the SOCAT Data Set and Gridded Data Viewers

1. What are the SOCAT Data Set and Gridded Data Viewers?
The SOCAT Data Set and Gridded Data Viewers provide an interactive, powerful visualization tool for the SOCAT data collection, hosted by a Live Access Server (LAS). Access is via the links on the different SOCAT version pages (e.g. for version 2020) under the Interactive header. There is also a video here showing how to use the Data Set Viewer and the Gridded Data Viewer.

2. What types of output can the SOCAT Data Set Viewer provide?
In the SOCAT Data Set Viewer you can make maps and property-property plots of selections of data, sub-set the data collection and download data sets. Data selections may be based upon constraints such as data set ID, vessel or platform name, season, data set quality control (QC) flag, space-time region, etc. Small or large subsets of the data can be downloaded. The SOCAT Data Set Viewer provides access to the quality control comments by SOCAT quality controllers. New functionality is constantly being added, and you can request new features, comment on current ones, and file bug reports via email to submit@socat.info.

3. How do I select data from specific data sets on the SOCAT Data Set Viewer?
Open the main SOCAT Data Set Viewer. On the left hand side, select “expocode” under the “by Dataset” label. A list of all possible expocodes will appear. You may filter expocodes by entering a search string into the “Filter” box. Select all the expocodes from which you would like to see data. Your selection will appear in the box “My selections”. Alternatively you may select data sets by region, vessel, investigator, etc. These selection criteria are available under the buttons on the left hand side, e.g. under the “by Dataset”, “by Region”, “by Metadata” buttons. On the top of the page, click “Update Plot” to update the map and subset those data sets from the collection.

4. How do I download data from the SOCAT Data Set Viewer?
Open the main SOCAT Data Set Viewer and select the data set(s) you would like to download, as described above. On the top of the page, click “Save As…” to download all the data from those data sets in a tab delimited text file.

5. How do I obtain the metadata and quality control comments for specific data sets?
Open the main SOCAT Data Set Viewer and select the data set(s) you are interested in, as described above. On the top of the page, click “Table of Datasets”. This will open the Table of Datasets page, listing the data sets.

For metadata: Click on the “Documentation” link accompanying the data set you are interested in. This will open up a file browser that will provide access to the metadata files for that data set.

For quality control comments: Click on the “Examine QC Flags” link accompanying the data set you are interested in. This will open up a file browser with the quality control comments for that data set. Quality control comments entered as part of earlier SOCAT versions will appear by clicking on “Show all versions”.