The role of mesoscale eddies in Southern Ocean Carbon fluxes from autonomous ocean gliders

南大洋被认为吸收了全球所有人类(人为)二氧化碳的40%和人为热量的75%，因此在持续缓解大气二氧化碳水平上升和相关气候影响方面具有不成比例的影响。因此，二氧化碳通量是多个过程的微妙平衡；温度驱动的溶解度效应、垂直营养物质供应驱动的生物碳减少、再矿化碳的上升流排放、海冰形成和融化以及大范围翻转或中尺度涡流等环流特征共同导致通量估计变得困难和高度不确定。我们对它们当前状态和未来行为的理解受到观测的空间和时间稀疏性以及模型无法复制它们的限制，特别是由循环驱动的生物效应。最近，生物地球化学浮标(每10天对水柱顶部2000米进行采样)极大地扩大了数据覆盖面，并导致了新的通量估计，表明区域二氧化碳汇比之前认为的要小得多。然而，浮动抽样策略被认为不足以捕捉短暂的主要通量事件和特征(如涡流)的强度及其发生的可变性，这可能会损害它们的估计。高频滑翔机观测提供了填补这些空白的机会，从而调和了综合观测预算估计和生物地球化学模型之间的差异，并减少了通量估计中的不确定性。

The Southern Ocean (SO) is thought to account for the uptake of ~40% of all global human-derived (anthropogenic) carbon dioxide and >75% of anthropogenic heat, thus being disproportionately influential in the ongoing mitigation of increasing atmospheric CO2 levels and related climate effects. SO CO2 fluxes are a delicate balance of multiple processes; temperature-driven solubility effects, biological carbon drawdown driven by vertical nutrient supply, upwelling-derived outgassing of remineralised carbon, sea-ice formation and melt, and circulation features such as large-scale overturning or mesoscale eddies together combine to make flux estimates difficult and highly uncertain. Our understanding of their present state and future behaviour are limited by both spatial and temporal sparsity of observations, and the inability of models to replicate them, particularly circulation-driven biological effects. Recently, biogeochemical floats (sampling the water column's top 2000m every 10 days) have massively increased data coverage and led to new flux estimates suggesting a much smaller regional CO2 sink than previously thought. However, float sampling strategies are thought to be insufficient to capture the intensity of short-lived major flux events and features (such as eddies), and the variability of their occurrence, which may compromise their estimates. High frequency glider observations offer the opportunity to fill these gaps, thereby reconciling disparities between integrated observational budget estimates and biogeochemical models, and reducing uncertainties in flux estimates.