BGC-06\INT-04 Ocean Health and Biological Carbon Pump with BGC-Argo
Integrated Analysis of Carbon Dioxide and Oxygen reveals Ocean Processes and Sensor Performance
Yingxu Wu* , Polar and Marine Research Institute, Jimei University, Xiamen, China; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
Di Qi, Polar and Marine Research Institute, Jimei University, Xiamen, China
Toby Tyrrell, Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK

The distributions of dissolved O2 and CO2 have not previously been systematically compared across the global surface ocean, despite their significance for life and climate. Here we analyze carbon dioxide and oxygen concentrations relative to saturation (equilibrium with the atmosphere) in surface waters, using two large datasets (ship-collected and float-collected data). When applied to a high-quality global ship-collected dataset, CO2 and O2 concentrations relative to saturation exhibit large seasonal and geographic variations. However, linear fits of CO2 and O2 deviations from saturation (ΔCO2 against ΔO2) yield y-intercepts close to zero, which suggests a requirement for data validity. We utilize this finding to investigate the accuracy of carbonate system data from biogeochemical-Argo floats. We find significant discrepancies in ΔCO2-ΔO2 y-intercepts compared to the global reference, implying overestimations of float-based CO2 release in the Southern Ocean. We conclude that this technique can be applied to data from autonomous platforms for quality assessment.