A Decade of Air-Sea pCO2 Observations from OOI’s Coastal Endurance Array
OOI has released a newly refined, quality-controlled dataset documenting ten years of air-sea pCO2 measurements from the Coastal Endurance Array off Oregon and Washington. Tracking coastal ocean acidification has been a goal for the array since operations began in 2015, and these long-term moored records now provide one of the most comprehensive views of air and surface seawater pCO2 and supporting environmental variables available in the Pacific Northwest.
This release includes measurements collected at four mooring sites, two off central Washington and two off central Oregon, positioned across the mid-shelf and continental slope to capture both along-shelf and cross-shelf variability. These time series highlight the dominant influence of seasonal and event-scale upwelling, which can elevate near-surface pCO2 to more than three times atmospheric levels and depress surface pH toward the aragonite saturation threshold. The record spans several notable marine heatwaves, offering insight into how warming anomalies interact with upwelling to shape coastal carbonate chemistry.
To build this dataset, OOI conducted extensive post-processing and human-in-the-loop quality control. This work involved correcting subtle sensor drifts and offsets, restoring usable data that had been removed for fixable issues, and checking the measurements against historical records, bottle samples, collocated instruments, and engineering diagnostics. All measurements were then merged onto an hourly time base to create a consistent, analysis-ready product suitable for research, modeling, and education.
In addition to pCO2, the dataset includes sea surface temperature, salinity, wind speed, and several derived carbonate system variables, such as estimated total alkalinity, and air–sea CO2 fluxes. These enhancements make it possible to explore marine carbonate system parameters without additional processing and allow users to evaluate physical drivers of variability.
The data are available in both NetCDF and Zarr formats for each mooring site, with updated metadata and documentation. In the near future, we plan to expand on this dataset to include inshore pCO2, near surface pH, and subsurface measurements.
For access to this dataset and all OOI community data products, visit the OOI collection in Zenodo.
Figure 1. Cross-comparing the mooring observations against the discrete samples and SOCAT v2025 dataset.
_
Figure 2. Time series of observations at the Oregon Shelf Surface Mooring (CE02SHSM) of sea surface temperature, salinity, estimated total alkalinity, air and surface pCO2, ocean to atmosphere CO2 flux, and 10 m, normalized wind speed. Black dots and stars are discrete samples collected during mooring maintenance cruises. Dark red dots are from the SOCAT v2025 dataset. Light grey lines in the surface temperature and wind speed records are from the NDBC Stonewall Bank (46050) Mooring.
_______________________________
References:
Bakker, Dorothee C. E.; Alin, Simone R.; Aramaki, Takafumi; Barbero, Leticia; Bates, Nicholas; Gkritzalis, Thanos; Jones, Steve D.; Kozyr, Alex; Lauvset, Siv K.; Macovei, Vlad A.; Metzl, Nicolas; Munro, David R.; Nakaoka, Shin-ichiro; O’Brien, Kevin M.; Olsen, Are; Pierrot, Denis; Steinhoff, Tobias; Sullivan, Kevin F.; Sutton, Adrienne J.; Sweeney, Colm; Wada, Chisato; Wanninkhof, Rik; Akl, John; Arbilla, Lisandro A.; Azetsu-Scott, Kumiko; Battisti, Roman; Beatty, Cory M.; Becker, Meike; Benoit-Cattin, Alice; Berghoff, Carla F.; Bittig, Henry C.; Bonin, Jennifer A.; Bott, Randy; Bozzano, Roberto; Burger, Eugene F.; Brunetti, Fabio; Cantoni, Carolina; Castelli, Giuliano; Chambers, Don P.; Chierici, Melissa; Corbo, Andrea; Cronin, Margot; Cross, Jessica N.; Currie, Kim I.; Dentico, Carlotta; Emerson, Steven R.; Enochs, Ian C.; Enright, Matt P.; Enyo, Kazutaka; Ericson, Ylva; Evans, Wiley; Fay, Amanda R.; Feely, Richard A.; Fragiacomo, Elena; Fransson, Agneta; Gehrung, Martina; Giani, Michele; Glockzin, Michael; Hamnca, Siyabulela; Holodkov, Nikola; Hoppema, Mario; Ibánhez, J. Severino P.; Kadono, Koji; Kamb, Linus; Kralj, Martina; Kristensin, Tor O.; Laudicella, V. Alessandro; Lefèvre, Nathalie; Leseurre, Coraline; Lo Monaco, Claire; Maenner Jones, Stacy; Maenza, Reinaldo A.; McAuliffe, Anna M.; Mdokwana, Baxolele; Monacci, Natalie M.; Musielewicz, Sylvia; Neill, Craig; Newberger, Tim; Nojiri, Yukihiro; Ohman, Mark D.; Ólafsdóttir, Sólveig R.; Olivier, Léa; Omar, Abdirahman M.; Osborne, John; Pensieri, Sara; Petersen, Wilhelm; Plueddemann, Albert J.; Rehder, Gregor; Roden, Nicholas P.; Rutgersson, Anna; Sallée, Jean-Baptiste; Sanders, Richard; Sarpe, Dick; Schirnik, Carsten; Schlitzer, Reiner; Send, Uwe; Skjelvan, Ingunn; Sutherland, Stewart, C.; T’Jampens, Michiel; Tamsitt, Veronica; Telszewski, Maciej; Theetaert, Hannelore; Tilbrook, Bronte; Trull, Tom; Tsanwani, Mutshutshu; Van de Velde, Sebastiaan; Van Heuven, Steven M. A. C.; Veccia, Martín H.; Voynova, Yoana G.; Weller, Robert A.; Williams, Nancy L. (2025). Surface Ocean CO2 Atlas Database Version 2025 (SOCATv2025) (NCEI Accession 0304549). NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/648f-fv35.