Understanding the ocean carbon sink and its future acidification-derived changes requires accurate and precise measurements with good spatiotemporal coverage. In addition, a deep knowledge of the thermodynamics of the seawater carbonate system is key to interconverting between measured and calculated variables. To gain insights into the remaining inconsistencies in the seawater carbonate system, we assess discrete water column measurements of carbon dioxide fugacity (fCO₂), dissolved inorganic carbon (DIC), total alkalinity (TA), and pH measured with unpurified indicators, from hydrographic cruises in the Atlantic, Pacific, and Southern Oceans included in GLODAPv2.2020 (19,013 samples). An agreement of better than ± 3% between fCO₂ measured and calculated from DIC and pH is obtained for 94% of the compiled dataset, while when considering fCO₂ measured and calculated from DIC and TA, the agreement is better than ± 4% for 88% of the compiled dataset, with a poorer internal consistency for high-CO₂ waters. Inspecting all likely sources of uncertainty from measured and calculated variables, we conclude that the seawater carbonate system community needs to (i) further refine the thermodynamic model of the seawater carbonate system, especially K₂, including the impact of organic compounds and other acid-base systems on TA; (ii) update the standard operating procedures for the seawater carbonate system measurements following current technological and analytical advances, paying particular attention to the pH methodology that is the one that evolved the most; (iii) encourage measuring discrete water column fCO₂ to further check the internal consistency of the seawater carbonate system, especially given the new era of sensor-based seawater measurements; and (iv) develop seawater Certified Reference Materials (CRMs) for fCO₂ and pH together with seawater CRMs for TA and DIC over the range of values encountered in the global ocean. Our conclusions also suggest the need for a re-evaluation of the adjustments applied by GLODAPv2 to pH, which were based on DIC and TA consistency checks but not supported by fCO₂ and DIC consistency.

了解海洋碳汇及其未来酸化衍生的变化需要准确和精确的测量以及良好的时空覆盖。此外，对海水碳酸盐系统热力学的深入了解是测量变量和计算变量之间相互转换的关键。为了深入了解海水碳酸盐系统中剩余的不一致性，我们评估了二氧化碳逸度 ( f CO ₂ )、溶解无机碳(DIC)、总碱度 (TA) 和使用未纯化指标测量的 pH 值的离散水柱测量值，来自GLODAPv2.2020 中包含的大西洋、太平洋和南大洋的水文巡航（19,013 个样本）。f CO之间的一致性优于 ± 3%₂从 DIC 测量和计算得到 94% 的编译数据集，而当考虑从 DIC 和 TA 测量和计算的f CO ₂时，88% 的编译数据集的一致性优于 ± 4%，具有高CO ₂水的内部稠度较差。通过测量和计算变量检查所有可能的不确定性来源，我们得出结论，海水碳酸盐系统社区需要（i）进一步完善海水碳酸盐系统的热力学模型，尤其是 K ₂，包括有机化合物和其他酸碱体系对TA的影响；(ii) 根据当前的技术和分析进展更新海水碳酸盐系统测量的标准操作程序，特别注意发展最多的 pH 方法；(iii) 鼓励测量离散水柱f CO ₂以进一步检查海水碳酸盐系统的内部一致性，特别是考虑到基于传感器的海水测量的新时代；(iv) 开发用于f CO _{2的海水认证参考物质 (CRM)}和 pH 值以及海水 CRM 的 TA 和 DIC 在全球海洋中遇到的值范围内。我们的结论还表明需要重新评估 GLODAPv2 对 pH 值的调整，这些调整基于 DIC 和 TA 一致性检查，但不支持f CO ₂和 DIC 一致性。