On behalf of more than 100 contributing scientists worldwide, we proudly announce the release of Version 6 of the Surface Ocean CO₂ Atlas (SOCAT). SOCAT (www.socat.info) is a synthesis activity by international marine carbon scientists with annual public releases. SOCAT version 6 has 23.4 million quality-controlled in situ surface ocean fCO₂ (fugacity of carbon dioxide) measurements from 1957 to 2017 for the global oceans and coastal seas, as well as additional calibrated sensor fCO₂ measurements. The poster handout has further details on version 6 key features, findings and other information.

The SOCAT website (www.socat.info) provides access to synthesis and gridded data products. Users can explore the data products via powerful, interactive online viewers, the Data Set Viewer and the Gridded Data Viewer. Alternatively, users can download of the synthesis and gridded products with Matlab code available for reading these files. An article in Earth System Science Data (ESSD) by Bakker et al. (2016) documents the data products and quality control criteria in SOCAT version 3, which also apply to versions 4 to 6. Users are kindly asked to follow the SOCAT Fair Data Use Statement by generously acknowledging the contribution of SOCAT scientists by invitation to co-authorship, especially for data providers in regional studies.

SOCAT scientific community has made a Voluntary Commitment of 'Annual, public releases of the Surface Ocean CO₂ Atlas (SOCAT)' to the UN Ocean Conference (#OceanAction20464). SOCAT enables quantification of the ocean carbon sink, ocean acidification, and evaluation of ocean biogeochemical models in a changing world. SOCAT represents a milestone in biogeochemical and climate research and in informing policy. However, SOCAT remains without sustained funding and as such, the effort is at risk.

Data submission for SOCAT version 7 ends 15 January 2019, while version 7 quality control ends 31 March 2019.