Since 2004, the Service facility SNAPO-CO2 (Service National d’Analyse des Paramètres Océaniques du CO2) housed by the LOCEAN laboratory (Paris, France) has been in charge for the analysis of Total Alkalinity (AT) and Total dissolved inorganic carbon (CT) of seawater samples on a series of cruises or ships of opportunity conducted in different regions in the frame of French projects. More than 44000 observations are synthetized in this work. Sampling was performed either from CTD-Rosette casts (Niskin bottles) or collected from the ship’s seawater supply (intake at about 5m depth). After completion of each cruise, discrete samples were returned back at LOCEAN laboratory and stored in a dark room at 4 °C before analysis generally within 2-3 months after sampling (sometimes within a week).  AT and CT were analyzed simultaneously by potentiometric titration using a closed cell (Edmond, 1970). Certified Reference Materials (CRMs) provided by Pr. A. Dickson (Scripps Institution of Oceanography, San Diego, USA) were used to calibrate the measurements. The same instrumentation was used for underway measurements during OISO cruises (https://doi.org/10.18142/228) and OISO AT-CT data for 1998-2018 in the South Indian Ocean added in this synthesis. The synthesis is organized in two files (one for Global ocean and the Coastal Zones, one for the Mediterranean Sea) with the same format: Cruise name, Ship name, day, month, year, hour, minute, second, latitude, longitude, depth, AT (µmol/kg), Flag-AT, CT (µmol/kg), Flag-CT, Temperature (°C), Flag-Temp, Salinity (PSU), Flag-Salinity, nsample/cruise, nsample on file, sampling method.

The SURATLANT dataset (SURveillance ATLANTique) consists of individual data of temperature, salinity, dissolved inorganic carbon (DIC) and its isotopic composition d13CDIC, total alkalinity (At), inorganic nutrients and water stable isotopes (δ18O and δD) collected mostly from ships of opportunity since 1993 along transects between Iceland and Newfoundland (shipping company EIMSKIP), as well as, since 2014, between west Greenland and Danemark (shipping company RAL). The data have been validated, qualified, and their accuracy and the overall characteristics of the data set are presented in a paper (Reverdin et al., 2018). The csv file provides a listing of the data with one line for each collection date. This includes collection date, position, temperature, salinity, and the measured, validated and in some cases adjusted variables, as well as a quality code following WOCE/GLODAP format. For water isotopes and isotopic composition of inroganic carbon, a code is also provided indicating the method of measurement used. An additional text-file provides a normalized average seasonal cycle of the 10 variables measured in 5 boxes between the vicinity of Newfoundland to the south-west of Iceland (corresponding to the figure 3 of the paper Reverdin et al in the References). Format and information is provided in the top 25 lines and the gridded seasonal cyle data start at line 26.