The Southern Ocean is an important region of ocean carbon uptake, and observations indicate its air‐sea carbon flux fluctuates from seasonal to decadal timescales. Carbon fluxes at regional scales remain highly uncertain due to sparse observation and intrinsic complexity of the biogeochemical processes. The objective of this study is to better understand the mechanisms influencing variability of carbon uptake in the Drake Passage. A regional circulation and biogeochemistry model is configured at the lateral resolution of 10 km, which resolves larger mesoscale eddies where the typical Rossby deformation radius is (50 km). We use this model to examine the interplay between mean and eddy advection, convective mixing, and biological carbon export that determines the surface dissolved inorganic carbon and partial pressure of carbon dioxide variability. Results are validated against in situ observations, demonstrating that the model captures general features of observed seasonal to interannual variability. The model reproduces the two major fronts: Polar Front (PF) and Subantarctic Front (SAF), with locally elevated level of eddy kinetic energy and lateral eddy carbon flux, which play prominent roles in setting the spatial pattern, mean state and variability of the regional carbon budget. The uptake of atmospheric CO₂, vertical entrainment during cool seasons, and mean advection are the major carbon sources in the upper 200 m of the region. These sources are balanced by the biological carbon export during warm seasons and mesoscale eddy transfer. Comparing the induced advective carbon fluxes, mean flow dominates in magnitude, however, the amplitude of variability is controlled by the eddy flux.

中文翻译：

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Drake通道pCO2变异的物理和生物控制

南大洋是海洋碳吸收的重要区域，观测表明其海海碳通量从季节到十年的时间尺度波动。由于稀疏的观测和生物地球化学过程的内在复杂性，区域尺度的碳通量仍然高度不确定。这项研究的目的是更好地了解影响德雷克海峡碳​​吸收变化的机制。在10 km的横向分辨率下配置了区域循环和生物地球化学模型，该模型解析了较大的中尺度涡流，其中典型的Rossby变形半径为（50公里）。我们使用该模型来检验均值和涡流对流，对流混合以及生物碳输出之间的相互作用，这些因素决定了表面溶解的无机碳和二氧化碳分压的可变性。针对现场观测结果验证了结果，表明该模型捕获了观测到的季节性至年际变化的一般特征。该模型再现了两个主要前沿：极地锋（PF）和亚南极锋（SAF），其涡动能和横向涡流的局部水平升高，在设定空间格局，平均状态和变异性方面起着重要作用。区域碳预算。大气中CO ₂的吸收，凉季的垂直夹带和平均对流是该区域上部200 m的主要碳源。这些来源通过温暖季节的生物碳出口和中尺度涡旋转移来平衡。比较诱导的对流碳通量，平均流量在大小上占优势，但是，可变性的幅度由涡流控制。