The Surface Ocean CO₂ Atlas (SOCAT) is a synthesis activity for quality-controlled, surface ocean fCO₂ (fugacity of carbon dioxide) observations by the international marine carbon research community (>100 contributors). SOCAT data is publicly available, discoverable and citable. SOCAT enables quantification of the ocean carbon sink and ocean acidification and evaluation of ocean biogeochemical models. SOCAT, which celebrated its 15th anniversary in 2022, represents a milestone in biogeochemical and climate research and in informing policy.
SOCAT data are released in versions. Each succeeding version contains new data sets as well as updates of older ones. The first version of SOCAT was released in 2011, the second and third version followed biennially. Automation allowed annual public releases since version 4. The latest SOCAT version (version 2026) has 44 million observations from 1957 to 2025 with an estimated accuracy of <±5 µatm for the global oceans and coastal seas. 8.4 million calibrated sensor observations (with estimated accuracy of ±5-10 µatm) are also available.
SOCAT version 2026 was released on the 16th of June 2026, containing data submitted on or before 16th of January 2026. New data submissions are welcome at any time and will be included in the next SOCAT release.
The submission deadline for v2027 is 15 January 2027.
SOCAT is a core Global Ocean Observing System data product for biogeochemistry endorsed by the Global Ocean Observing System GOOS.
The Surface Ocean CO2 Observing Network (SOCONET), the Surface Ocean CO2 Atlas (SOCAT) and the Surface Ocean CO2 Mapping (SOCOM) program are linked international efforts that, along with additional critical data from satellites, models and re-analysis, enable the routine delivery of ocean carbon and carbonate system data products. The loss of any activity (SOCONET, SOCAT, or SOCOM) or data source (satellite, in situ, or re-analysis) would prevent delivery of data products to global or regional assessments (Global Carbon Budget, IPCC, and others) that guide policy decisions. SOCONET, SOCAT and SOCOM are endorsed by the International Ocean Carbon Coordination Project (IOCCP, an Infrastructural Project of the Scientific Committee on Oceanic Research) and the Global Ocean Observing System (GOOS) Biogeochemistry Panel. The many researchers, funders, and agencies responsible for these activities and data are thanked for their contributions.