We are happy to inform you that the Surface Ocean CO₂ Atlas (SOCAT; www.socat.info) has released an updated cookbook for data quality control procedures. The updated cookbook, which applies from version 7 onward, was prepared by a team led by Siv Lauvset (Bergen, Norway). There is no intention to retrospectively implement the revised quality control criteria for data sets in SOCAT versions 1-6. We also kindly remind you that the deadline for quality control of SOCAT version 7 is 31 March 2019.

You can download the updated cookbook from the SOCAT site HERE.

Consistent quality control and the adequate quality control comments fully justifying all quality control steps are extremely important. Compared to the previous version of the SOCAT cookbook, the major differences in criteria are

• For flags A and B (accuracy estimate of better than 2 µatm) the overall warming between in situ and measurement should be <1 °C.
• For flags C and D (accuracy estimate of better than 5 µatm) the non-zero standard gas should preferably cover the entire range of observations, but the observations can be up to 20% outside the certified standard gas value.