A uniform, quality controlled Surface Ocean CO₂ Atlas (SOCAT)

A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO₂) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO₂ Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO₂, which had been subject to quality control (QC). Many additional CO₂ data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO₂ data points from the global oceans and coastal seas, spanning four decades (1968–2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO₂ data collection and the importance of quantifying net global oceanic CO₂ uptake and its changes, sustained data synthesis and data access are priorities.