The CARINA (CARbon dioxide IN the Atlantic Ocean) data synthesis project is an international collaborative effort of the EU IP CARBOOCEAN, and US partners, including the PMEL carbon group. It has produced a merged internally consistent data set of open ocean subsurface measurements for biogeochemical investigations, in particular, studies involving the carbon system. The original focus area was the North Atlantic Ocean, but over time the geographic extent expanded and CARINA now includes data from the entire Atlantic, the Arctic Ocean, and the Southern Ocean.

The CARINA database includes data from 188 cruises. The salinity, oxygen, nutrient, inorganic carbon system and CFC data have been subjected to extensive quality control and adjustments have been made when necessary. Many of the procedures used during CARINA were adopted from GLODAP, however, the number of cruises included in CARINA combined with the additional manpower and funding available from CARBOOCEAN allowed improvements. The most significant changes were:

• more parameters were subjected to 2nd QC;
• software was designed to automate portions of the 2nd QC procedures;
• work was coordinated among the different groups and within groups by means of a Web site;
• pH was included in the final data products along with ALK and DIC;
• fully formatted versions of all the individual cruise files were submitted to both CCHDO and OCADS for archive and distribution; and
• a significant collection of references to literature describing the individual cruise results was compiled.

This effort created two distinct results. The first is a set of individual cruise files with the measured data converted to common units and accompanying metadata. The second is a set of 3 data products (Arctic Mediterranean Seas, Atlantic and Southern Ocean) that have been fully calibrated and include some calculated values (CARINA Data Products). The latter are compatible with the three GLODAP data products (Atlantic, Indian and Pacific). In addition, all of the individual cruise data files have been made available in WOCE exchange format in a single location (Cruise Summary Table) along with metadata and references. We strongly recommend users to employ the data products instead of the individual cruise files as the data in the latter have not been corrected for biases identified during the secondary QC. The CARINA effort is further described in the following as well as in the CARINA special issue of Earth System Science Data (ESSD) Journal.