The ocean is a sink for ~25% of the atmospheric CO2 emitted by human activities, an amount in excess of 2 petagrams of carbon per year (PgC yr−1). Time-resolved estimates of global ocean-atmosphere CO2 flux provide an important constraint on the global carbon budget. However, previous estimates of this flux, derived from surface ocean CO2 concentrations, have not corrected the data for temperature gradients between the surface and sampling at a few meters depth, or for the effect of the cool ocean surface skin. Here we calculate a time history of ocean-atmosphere CO2 fluxes from 1992 to 2018, corrected for these effects. These increase the calculated net flux into the oceans significantly.

This dataset includes CO2 Measurements in the Atmosphere and Surface Ocean Waters from Scripps Institution of Oceanography R/Vs Downwind, Monsoon, and Lusiad Expeditions, collected from HORIZON, SPENCER F. BAIRD, and ARGO in the Andaman Sea or Burma Sea, Arabian Sea, Bay of Bengal, Caribbean Sea, Indian Ocean, Laccadive Sea, Malacca Straits, Mozambique Channel, North Atlantic Ocean, North Pacific Ocean, Philippine Sea, Singapore Straits, South Atlantic Ocean, South China Sea (Nan Hai), South Pacific Ocean, Southern Oceans (> 60 degrees South) and Tasman Sea from 1957-10-21 to 1963-08-15. These data include AIR-SEA DIFFERENCE - PARTIAL PRESSURE (OR FUGACITY) OF CARBON DIOXIDE, BAROMETRIC PRESSURE, Partial pressure (or fugacity) of carbon dioxide - atmosphere, Partial pressure (or fugacity) of carbon dioxide - water and SEA SURFACE TEMPERATURE. The instruments used to collect these data include Carbon dioxide (CO2) gas analyzer and Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement. These data were collected by Charles D. Keeling of Scripps Institution of Oceanography (SIO) as part of the Keeling_1957_1963 dataset. CDIAC associated the following cruise ID(s) with this dataset: KEEL19571021

This dataset contains a combined globally mapped estimate of the air-sea exchange of carbon dioxide (CO2) based on Surface Ocean CO2 Atlas Database (SOCAT) partial pressure of CO2 (pCO2) and calculated pCO2 from Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemistry floats from 1982 to 2017. The pCO2 fields were created using a 2-step neural network technique. In a first step, the global ocean is divided into 16 biogeochemical provinces using a self-organizing map. In a second step, the non-linear relationship between variables known to drive the surface ocean carbon system and gridded observations from the SOCAT dataset (Bakker et al., 2016) starting in 1982 in various combinations with calculated pCO2 from biogeochemical ARGO floats starting in 2014 from the SOCCOM project (Johnson et al., 2017) is reconstructed using a feed-forward neural network within each province separately. The final product is then produced by projecting these driving variables, i.e., surface temperature, chlorophyll, mixed layer depth, and atmospheric CO2 onto oceanic pCO2 using these non-linear relationships. This results in monthly pCO2 fields at 1°x1° resolution covering the entire globe with the exception of the Arctic Ocean and few marginal seas. The air-sea CO2 flux is then computed using a standard bulk formula.

This dataset contains observation-based pCO2 data and a derived monthly climatology. The observation-based pCO2 fields were created using a 2-step neural network method extensively described and validated in Landschützer et al. 2013, 2014, 2016. The method first clusters the global ocean into biogeochemical provinces and in a second step reconstructs the non-linear relationship between CO2 driver variables and observations from the v2022 release of the Surface Ocean CO2 Atlas (SOCAT, Bakker et al. 2016). This file contains the resulting monthly pCO2 fields at 1°x1° resolution covering the global ocean for the first time including the Arctic Ocean and few marginal seas (see Landschützer et al 2020). The air-sea CO2 fluxes are computed from the air-sea CO2 partial pressure difference and a bulk gas transfer formulation following Landschützer et al. 2013, 2014, 2016. Furthermore, the monthly climatology is created from the monthly average of the period 1985-present.

Climatological mean monthly distributions of pH in the total H+ scale, total CO2 concentration (TCO2), and the degree of CaCO3 saturation for the global surface ocean waters (excluding coastal areas) are calculated using a data set for pCO2, alkalinity and nutrient concentrations in surface waters (depths less than 50 m), which is built upon the GLODAP, CARINA and LDEO database. The mutual consistency among these measured parameters is demonstrated using the inorganic carbon chemistry model with the dissociation constants for carbonic acid by Lueker et al. (2000) and for boric acid by Dickson (1990). The global ocean is divided into 24 regions, and the linear potential alkalinity (total alkalinity + nitrate) versus salinity relationships are established for each region. The mean monthly distributions of pH and carbon chemistry parameters for the reference year 2005 are computed using the climatological mean monthly pCO2 data adjusted to a reference year 2005 and the alkalinity estimated from the potential alkalinity versus salinity relationships. The climatological monthly mean values of pCO2 over the global ocean are compiled for a 4° x 5° grid for the reference year 2005, and the gridded data for each of 12 months are included in this database. This is updated version of Takahashi et al. (2009) for the reference year 2000 representing non-El Niño years using a database of about 6.5 million pCO2 data (less coastal areas of North and South America) observed in 1957-2012 (Takahashi et al., 2013). The equatorial zone (4°N-4°S) of the Pacific is excluded from the analysis because of the large interannual changes associated with the El Niño-Southern Oscillation events. The pH thus calculated ranges from 7.9 to 8.2. Lower values are located in the upwelling regions in the tropical Pacific and in the Arabian and Bering Seas; and higher values are found in the subpolar and polar waters during the spring-summer months of intense photosynthetic production. The vast areas of subtropical oceans have seasonally varying pH values ranging from 8.05 during warmer months to 8.15 during colder months. The warm tropical and subtropical waters are supersaturated by a factor of as much as 4.2 with respect to aragonite and 6.3 for calcite, whereas the cold subpolar and polar waters are less supersaturated only by 1.2 for aragonite and 2 for calcite because of the lower pH values resulting from greater TCO2 concentrations. In the western Arctic Ocean, aragonite undersaturation is observed.

This dataset contains a high-quality dataset of derived products from over a million observations of surface water partial pressure/fugacity of carbon dioxide (pCO2w/fCO2w), for the Caribbean Sea, Gulf of Mexico and North-East Atlantic Ocean covering the timespan from 2003-03-01 to 2019-12-30. Prior to installation of automated pCO2 systems on cruise ships of the Royal Caribbean Cruise Lines and subsidiaries (Explorer of the Seas, Celebrity Equinox, Allure of the Seas), very limited surface water carbon data were available in this region. With this observational program, the Northern Caribbean Sea has now become one of the best sampled regions for pCO2 of the world's ocean. The derived quantities include total alkalinity (TA), acidity (pH), aragonite saturation state (ΩAr) and air-sea CO2 flux.

This dataset includes Surface Ocean CO2 Atlas (SOCAT) version 2, a synthesis product of the surface water fugacity of CO2 (fCO2) for the global oceans and coastal seas from 1968-11-16 to 2011-12-31. The Surface Ocean CO2 Atlas (SOCAT) is an international effort, supported by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS), and the Integrated Marine Biogeochemistry and Ecosystem Research program (IMBER), to deliver a uniformly quality-controlled surface ocean CO2 database.

This dataset consists of the co-located surface discrete fCO2 at 20 ˚C and underway fCO2 measurements at sea surface temperature (SST) for 21 cruises spanning the Pacific, Atlantic, Indian Oceans and Gulf of Mexico from 1991-07-12 to 2020-04-15. In addition, calculated fCO2 from alkalinity (TA) and total dissolved inorganic carbon (DIC) are provided. The co-located discrete fCO2 at 20 ˚C and underway fCO2 measurements at SST are used to infer the temperature dependence of CO2. For the 21 cruises spanning the major ocean basins from 1992-2020 a temperature dependence of 4.13 ± 0.01 % ˚C-1 is determined in close agreement with a widely used previous empirical estimate of 4.23 ± 0.02 % ˚C-1 for North Atlantic surface water. No statistically significant dependence on temperature or inorganic carbon speciation of the surface water was discerned as dependency on these factors is weak and it was masked by a range of overlapping temperatures and chemical compositions. The temperature dependency of calculated fCO2 yield a dependency of 4.10 % ˚C-1 for 17 cruises where there are co-located measurements of fCO2, alkalinity (TA) and dissolved inorganic carbon (DIC).

Approximately 14.2 million measurements of surface water pCO2 made over the global oceans during 1957-2019 have been processed to make a uniform data file in this Version 2019. Measurements made in open oceans as well as in coastal waters are included. The data assembled include only those measured using equilibrator-CO2 analyzer systems, and have been quality-controlled based upon the stability of the system performance, the reliability of calibrations for CO2 analysis and the internal consistency of data. We have added 567,632 data points comprised of 158 leg/cruise segments in this version. All of these were collected on the 4 ships in our current field program. These 4 ships operate primarily in high latitudes in both hemispheres and have built decades long records in these areas. R/V Nathaniel B. Palmer’s system has been operating since 1995, R/V Laurence M. Gould’s system since 2001, USCGC Healy since 2011, R/V M. Langseth since 2010 (terminated in 2018), and R/V Sikuliaq since 2015. Our contribution to this database through many years of 3.31 million records is primarily for the polar and sub-polar seas. These underway data have been quality controlled and corrected for the time lag and temperature differences between the water intake and pCO2 measurements. In order to allow re-examination of the data in the future, a number of measured parameters relevant to pCO2 in seawater are listed. The overall uncertainty for the pCO2 values listed is estimated to be ± 2.5 uatm on the average. The names and institutional affiliations of the contributors are listed in Table 1. The documentation for the previous versions (V1.0, V2007, V2008, V2009, V2010, V2011, V2012, V2013, V2014, V2015, V2016, V2017, and V2018) of our database are available at NCEI via Ocean Carbon data System (OCADS) LDEO Database web page. The global pCO2 dataset is available free of charge as a numeric data package (NDP) from the OCADS: https://www.ncei.noaa.gov/access/ocean-carbon-data-system/oceans/LDEO_Underway_Database/. The NDP consists of the oceanographic data files and this printed documentation, which describes the procedures and methods used to obtain the data.