Inorganic carbon and alkalinity measurements (in micromoles/kg) from Brazilian cruises in the Western Tropical Atlantic.

Inorganic carbon and alkalinity measurements (in micromoles/kg) along the coast of Brazil, 2013-2015.  

Carbon parameters along the track of merchant ships

In recent years, large datasets of in situ marine carbonate system parameters (partial pressure of CO2 (pCO2), total alkalinity, dissolved inorganic carbon and pH) have been collated. These carbonate system datasets have highly variable data density in both space and time, especially in the case of pCO2, which is routinely measured at high frequency using underway measuring systems. This variation in data density can create biases when the data are used, for example for algorithm assessment, favouring datasets or regions with high data density. A common way to overcome data density issues is to bin the data into cells of equal latitude and longitude extent. This leads to bins with spatial areas that are latitude and projection dependent (eg become smaller and more elongated as the poles are approached). Additionally, as bin boundaries are defined without reference to the spatial distribution of the data or to geographical features, data clusters may be divided sub-optimally (eg a bin covering a region with a strong gradient). To overcome these problems and to provide a tool for matching in situ data with satellite, model and climatological data, which often have very different spatiotemporal scales both from the in situ data and from each other, a methodology has been created to group in situ data into ‘regions of interest’, spatiotemporal cylinders consisting of circles on the Earth’s surface extending over a period of time. These regions of interest are optimally adjusted to contain as many in situ measurements as possible. All in situ measurements of the same parameter contained in a region of interest are collated, including estimated uncertainties and regional summary statistics. The same grouping is done for each of the other datasets, producing a dataset of matchups. About 35 million in situ datapoints were then matched with data from five satellite sources and five model and re-analysis datasets to produce a global matchup dataset of carbonate system data, consisting of 287,000 regions of interest spanning 54 years from 1957 to 2020. Each region of interest is 100 km in diameter and 10 days in duration. An example application, the reparameterisation of a global total alkalinity algorithm, is shown. This matchup dataset can be updated as and when in situ and other datasets are updated, and similar datasets at finer spatiotemporal scale can be constructed, for example to enable regional studies. This dataset was funded by ESA Satellite Oceanographic Datasets for Acidification (OceanSODA) project which aims at developing the use of satellite Earth Observation for studying and monitoring marine carbonate chemistry. **This version is now superseded by the version 4 with higher spatial and temporal resolution**

In recent years, large datasets of in situ marine carbonate system parameters (partial pressure of CO2 (pCO2), total alkalinity, dissolved inorganic carbon and pH) have been collated. These carbonate system datasets have highly variable data density in both space and time, especially in the case of pCO2, which is routinely measured at high frequency using underway measuring systems. This variation in data density can create biases when the data are used, for example for algorithm assessment, favouring datasets or regions with high data density. A common way to overcome data density issues is to bin the data into cells of equal latitude and longitude extent. This leads to bins with spatial areas that are latitude and projection dependent (eg become smaller and more elongated as the poles are approached). Additionally, as bin boundaries are defined without reference to the spatial distribution of the data or to geographical features, data clusters may be divided sub-optimally (eg a bin covering a region with a strong gradient). To overcome these problems and to provide a tool for matching in situ data with satellite, model and climatological data, which often have very different spatiotemporal scales both from the in situ data and from each other, a methodology has been created to group in situ data into ‘regions of interest’, spatiotemporal cylinders consisting of circles on the Earth’s surface extending over a period of time. These regions of interest are optimally adjusted to contain as many in situ measurements as possible. All in situ measurements of the same parameter contained in a region of interest are collated, including estimated uncertainties and regional summary statistics. The same grouping is done for each of the other datasets, producing a dataset of matchups. About 35 million in situ datapoints were then matched with data from five satellite sources and five model and re-analysis datasets to produce a global matchup dataset of carbonate system data, consisting of 287,000 regions of interest spanning 54 years from 1957 to 2023. Each region of interest is 50 km in diameter and 5 days in duration, improving the spatial and temporal resolution of the previous version (v3.4). The list of sources added in this dataset includes: - sea surface temperature and sea ice concentration from Copernicus Climate Service Multi-satellite L4 (http://dx.doi.org/10.5285/62c0f97b1eac4e0197a674870afe1ee6) - sea surface salinity from the Copernicus Marine service Multi Observation Global Ocean Sea Surface Salinity and Sea Surface Density (https://doi.org/10.48670/moi-00051) - Surface ocean sea-air CO2 fluxes and total alkalinity from ETH Zurich OceanSODA-ETHZ-v2 gridded dataset (https://doi.org/10.5281/zenodo.11206366) - salinity and mixed layer depth from SODA v3.4.2 reanalysis (https://doi.org/10.1175/JCLI-D-18-0149.1) - chlorophyll-A from ESA Ocean Colour CCI v6 (doi:10.3390/s19194285) - wind at 10 m and mean sea level pressure from ERA5 reanalysis - nitrate, silicate, phosphate, oxygen, temperature and salinity from World Ocean Atlas 2018 - sea level anomaly from Global Ocean Gridded L4 Sea Surface Heights And Derived Variables Multi-Year dataset by Copernicus Marine Service Information (https://doi.org/10.48670/moi-00148) - sea surface salinity from ESA Salinity CCI L4 v3.2.1 (https://dx.doi.org/10.5285/5920a2c77e3c45339477acd31ce62c3c) - sea surface salinity from JPL SMAP Level 3 CAP Sea Surface Salinity (https://doi.org/10.5067/SMP40-3SPCS) - temperature and salinity from Coriolis Observation Re-Analysis CORA5.2 by Copernicus Marine Service (https://doi.org/10.17882/46219) - subskin sea surface temperature from NOAA OISST SST (http://doi.org/10.5067/GHAAO-4BC01) - sea surface salinity from the Arctic salinity dataset (https://doi.org/10.20350/digitalCSIC/9065) the Barcelona Expert Center (http://bec.icm.csic.es/) - pH and spCO2 from Copernicus Marine Service Surface Ocean Carbon Dataset (https://doi.org/10.48670/moi-00047) An example application, the reparameterisation of a global total alkalinity algorithm, is shown. This matchup dataset can be updated as and when in situ and other datasets are updated, and similar datasets at finer spatiotemporal scale can be constructed, for example to enable regional studies. This dataset was funded by ESA OceanHealth / Ocean Acidification project which aims at developing the use of satellite Earth Observation for studying and monitoring marine carbonate chemistry.

This set of data documents the radiocarbon dates (n=19) obtained thanks to the accelerator mass spectrometry method (AMS) at the LMC14/ARTEMIS French national facility on the cores (Multicorer, Kullenberg) retrieved from the West-Gironde mud patch (WGMP) during the JERICObent-7 cruise (10-15 July 2019; NR Côtes de la Manche, https://doi.org/10.17600/18001022). The WGMP registers very high sedimentation rates since the last 600 years (≥ 0.3 cm/yr) and is thus of great interest for palaeoceanographic investigations. At present, this depocenter marks the mid-shelf of the temperate Bay of Biscay off major French rivers from the Aquitaine basin. The fine mud deposits of the WGMP are of 3 to 4 meters thick and lie on palimpsest levels rich in gravels and shells. They cover a V-shaped structure, oriented SW-NE, which is attributed to the incision(s) of a paleovalley in the Cenozoic substrate, mainly linked to the paleo-Gironde routing changes during past glacials/interglacials, and its potential past convergences with the paleo-rivers of the Antioche perthuis (Seudre, Charente paleovalleys?) at that times. Detailed information on each sample is presented with the 14C results obtained by the Artemis AMS facility at LMC14 laboratory (Dumoulin et al. 2017- https://doi.org/10.1017/RDC.2016.116, Beck et al. 2024- https://doi.org/10.1017/RDC.2023.23). Raw ages are indicated together with calibration calculations using the last two versions of the Calib software (http://calib.org/, Calib 7 and 8) to show the dispersion of ages linked to the updating of calibration curves (Marine13, Intcal13, Marine20, Intcal 20). The calibrated ages finally retained for publications (used in the related Seanoe document - https://doi.org/10.17882/104237 - and published in Eynaud et al., 2025 for the ST3c core, https://doi.org/10.1016/j.gloplacha.2025.105039) are those obtained with the last Calib 8.1 version. Raw 14C ages were calibrated and converted to calendar ages using the IntCal20 calibration curve with a reservoir age correction of 400 years deduced from Radionuclide analyses (137Cs and 210Pb) at the top of the studied cores (see Schmidt, 2025, https://www.seanoe.org/data/00968/107979/). 

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. 

This product contains observations and gridded files from two up-to-date carbon and biogeochemistry community data products: Surface Ocean Carbon ATlas SOCATv2023 and GLobal Ocean Data Analysis Project GLODAPv2.2023. The SOCATv2023-OBS dataset contains >25 million observations of fugacity of CO2 of the surface global ocean from 1957 to early 2023. The quality control procedures are described in Bakker et al. (2016). These observations form the basis of the gridded products included in SOCATv2023-GRIDDED: monthly, yearly and decadal averages of fCO2 over a 1x1 degree grid over the global ocean, and a 0.25x0.25 degree, monthly average for the coastal ocean. GLODAPv2.2023-OBS contains >1 million observations from individual seawater samples of temperature, salinity, oxygen, nutrients, dissolved inorganic carbon, total alkalinity and pH from 1972 to 2021. These data were subjected to an extensive quality control and bias correction described in Olsen et al. (2020). GLODAPv2-GRIDDED contains global climatologies for temperature, salinity, oxygen, nitrate, phosphate, silicate, dissolved inorganic carbon, total alkalinity and pH over a 1x1 degree horizontal grid and 33 standard depths using the observations from the previous major iteration of GLODAP, GLODAPv2. SOCAT and GLODAP are based on community, largely volunteer efforts, and the data providers will appreciate that those who use the data cite the corresponding articles (see References below) in order to support future sustainability of the data products.

The atmospheric fugacity of CO2 is measured underway with an autonomous system on board a merchant ship sailing from France to Brazil.

The fugacity of CO2 (fCO2) was measured underway during the PIRATA FR-32 cruise in the Eastern Tropical Atlantic using an infrared detection technique.