The Southern Ocean plays a fundamental role in the global carbon cycle, dominating the oceanic uptake of heat and carbon added by anthropogenic activities and modulating atmospheric carbon concentrations in past, present, and future climates. However, the remote and extreme conditions found there make the Southern Ocean perpetually one of the most difficult places on the planet to observe and to model, resulting in significant and persistent uncertainties in our knowledge of the oceanic carbon cycle there. The flow of carbon in the Southern Ocean is traditionally understood using a zonal mean framework, in which the meridional overturning circulation drives the latitudinal variability observed in both air–sea flux and interior ocean carbon concentration. However, recent advances, based largely on expanded observation and modeling capabilities in the region, reveal the importance of processes acting at smaller scales, including basin-scale zonal asymmetries in mixed-layer depth, mesoscale eddies, and high-frequency atmospheric variability. Assessing the current state of knowledge and remaining gaps emphasizes the need to move beyond the zonal mean picture and embrace a four-dimensional understanding of the carbon cycle in the Southern Ocean.

中文翻译：

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南大洋的四维碳循环


南大洋在全球碳循环中发挥着重要作用，主导着海洋对人为活动增加的热量和碳的吸收，并调节了过去、现在和未来气候中大气中的碳浓度。然而，那里发现的偏远和极端条件使南大洋永远是地球上最难观察和建模的地方之一，导致我们对那里的海洋碳循环的了解存在重大而持久的不确定性。传统上，南大洋的碳流动使用纬向平均框架来理解，其中经向翻转环流驱动了在气海通量和海洋内部碳浓度中观察到的纬度变化。然而，主要基于该地区扩展的观测和建模能力的最新进展揭示了在较小尺度上作用的过程的重要性，包括混合层深度的盆地尺度纬向不对称、中尺度涡流和高频大气变率。评估当前的知识状况和仍然存在的差距强调需要超越纬向平均图景，并接受对南大洋碳循环的四维理解。