资源环境科技发展态势分析平台

Determining air‐sea CO₂ fluxes using pCO₂ disequilibrium requires knowing the gas transfer velocity and air‐sea pCO₂ difference. Most pCO₂ measurements are made from ships, whose uncontaminated seawater intakes are located at >5‐m depth to prevent ingestion of air. However, there could be bias in our determination of CO₂ fluxes if there is disagreement between pCO₂ measurements at the surface and 5‐m. Seawater measurements made at the near‐surface and 5‐m in the eastern Equatorial Pacific Ocean show that precipitation can diluted surface seawater salinity, and lower the pCO₂ and dissolved inorganic carbon, and raise pH of the same water, and that these changes in ocean chemistry are largely missed by measurements at 5‐m. This finding implies that estimates of ocean CO₂ uptake might be underestimated, since rain will lower surface ocean pCO₂ in both source and sink regions, and hence increase uptake in sink regions and decrease outgassing in source regions.