The <scp> ICOS OTC <i>p</i> CO <sub>2</sub> </scp> instrument intercomparison

Abstract In 2021, the Ocean Thematic Centre of the European Research Infrastructure “Integrated Carbon Observation System” conducted an international partial pressure of carbon dioxide ( p CO 2 ) instrument intercomparison. The goal was to understand how different types of instrumentation for the measurement of ocean p CO 2 compare to each other. During the two‐week long experiment, we installed various instruments in a tank facility using natural sea water (North Sea). These included direct air–water equilibration systems and membrane‐based flow‐through instruments along with submersible sensors and instruments that are normally installed on buoys and autonomous surface vehicles. In situ instruments were installed inside the tank and the flow‐through instruments were fed the same water using a pumping system. We changed the temperature (between 10°C and 28°C) and the seawater p CO 2 (between 250 and 800 μ atm) to observe instrument responses over a wide range. Since there is no reference for surface ocean p CO 2 measurements, we agreed on a set of instruments serving as intercomparison reference. All data from the different instruments were then compared against the intercomparison reference during periods of stable temperature and p CO 2 . The study provides important information to enhance future ocean carbon monitoring networks, but makes no direct recommendation for the use of any specific sensor. A major finding is that equilibration through direct air–water contact appears to be more consistent and independent of external factors than equilibration through a membrane or photometric detection. We found several instruments with no temperature measurements at the location of equilibration or with uncalibrated temperature sensors introducing significant uncertainty in the results.

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Publication Details

Journal
Limnology and Oceanography Methods
Published
2025-08-30
DOI
https://doi.org/10.1002/lom3.10727
Citations
2
Primary Topic
Atmospheric and Environmental Gas Dynamics
Type
article
Field-Weighted Citation Impact
2.21

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article

The ICOS OTC p CO 2 instrument intercomparison

John Akl, Thanos Gkritzalis, Vlad A. Macovei, Carolina Cantoni et al.
2 citations
Limnology and Oceanography Methods
Atmospheric and Environmental Gas Dynamics
2.21
article

The ICOS OTC p CO 2 instrument intercomparison

John Akl, Thanos Gkritzalis, Vlad A. Macovei, Carolina Cantoni, Kiminori Shitashima, Adrienne J. Sutton, Sami Kielosto, Dariia Atamanchuk, Anna Rutgersson, Arne Körtzinger, Constantin Frangoulis, Ricardo Arruda, Noah Lawrence‐Slavas, Tobias Steinhoff, Andrew G. Dickson, Martti Honkanen, Rik Wanninkhof, Natalia Stamataki, Jac Fought, Maciej Telszewski, Bronte Tilbrook, Laurence Beaumont, Ute Schuster, Markus Ritschel, Mark A. Barry, Reggie S. Spaulding, Damien Malardé, Hannelore Theetaert, S. D. M. Jones, Siv K. Lauvset, Lucía Gutiérrez‐Loza, Richard Sanders, Peter Landschützer, Ken Stenbäck, Melf Paulsen, Nadja Kinski, Quanlong Li, Anna Luchetta, Craig Neill, C. P. HAGAN, Jana Fahning, Witold Tatkiewicz
article en
2 citations

Abstract

Abstract In 2021, the Ocean Thematic Centre of the European Research Infrastructure “Integrated Carbon Observation System” conducted an international partial pressure of carbon dioxide ( p CO 2 ) instrument intercomparison. The goal was to understand how different types of instrumentation for the measurement of ocean p CO 2 compare to each other. During the two‐week long experiment, we installed various instruments in a tank facility using natural sea water (North Sea). These included direct air–water equilibration systems and membrane‐based flow‐through instruments along with submersible sensors and instruments that are normally installed on buoys and autonomous surface vehicles. In situ instruments were installed inside the tank and the flow‐through instruments were fed the same water using a pumping system. We changed the temperature (between 10°C and 28°C) and the seawater p CO 2 (between 250 and 800 μ atm) to observe instrument responses over a wide range. Since there is no reference for surface ocean p CO 2 measurements, we agreed on a set of instruments serving as intercomparison reference. All data from the different instruments were then compared against the intercomparison reference during periods of stable temperature and p CO 2 . The study provides important information to enhance future ocean carbon monitoring networks, but makes no direct recommendation for the use of any specific sensor. A major finding is that equilibration through direct air–water contact appears to be more consistent and independent of external factors than equilibration through a membrane or photometric detection. We found several instruments with no temperature measurements at the location of equilibration or with uncalibrated temperature sensors introducing significant uncertainty in the results.

Limnology and Oceanography MethodsVol. 23(12)
Uppsala University (SE), CSIRO Oceans and Atmosphere (AU), Finnish Meteorological Institute (FI), Commonwealth Scientific and Industrial Research Organisation (AU), Flanders Marine Institute (BE), Centre National de la Recherche Scientifique (FR), Dalhousie University (CA), Scripps Institution of Oceanography (US), Universität Hamburg (DE), Xiamen University (CN), National and Kapodistrian University of Athens (GR), University of Exeter (GB), NOAA Pacific Marine Environmental Laboratory (US), Bjerknes Centre for Climate Research (NO), Bedford Institute of Oceanography (CA), Finnish Environment Institute (FI), NOAA Atlantic Oceanographic and Meteorological Laboratories (US), GEOMAR Helmholtz Centre for Ocean Research Kiel (DE), Sensors (United States) (US), Sopot University of Applied Science (PL), NORCE Research AS (NO), Istituto di Scienze Marine del Consiglio Nazionale delle Ricerche (IT), Délégation Ile-de-France Sud (FR), NKE Instrumentation (France) (FR), Hellenic Centre for Marine Research (GR), Helmholtz-Zentrum Hereon (DE), Cape Town Science Centre (ZA), Clinical Research Center Kiel (DE), University of Bergen (NO), Tokyo University of Marine Science and Technology (JP), University of Montana (US)
National Science Foundation, Vlaams Instituut voor de Zee, Canada Foundation for Innovation, University of Exeter, Canada Excellence Research Chairs, Government of Canada, Dalhousie University, Fonds Wetenschappelijk Onderzoek, Vetenskapsrådet, Norges Forskningsråd, Helmholtz Association, Vlaamse regering, National Oceanic and Atmospheric Administration, HORIZON EUROPE Framework Programme, Natural Environment Research Council, National Key Research and Development Program of China, NOAA Pacific Marine Environmental Laboratory, HORIZON EUROPE Climate, Energy and Mobility
Openalex Percentile: Top 12%
Atmospheric and Environmental Gas Dynamics
2.21
DOIOpen Access PDFOpenAlex
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