The ocean response to carbon emissions involves the combined effect of an increase in atmospheric CO₂, acting to enhance the ocean carbon storage, and climate change, acting to decrease the ocean carbon storage. This ocean response can be characterised in terms of a carbon–concentration feedback and a carbon–climate feedback. The contribution from different ocean basins to these feedbacks on centennial timescales is explored using diagnostics of ocean carbonate chemistry, physical ventilation and biological processes in 11 CMIP6 Earth system models. To gain mechanistic insight, the dependence of these feedbacks on the Atlantic Meridional Overturning Circulation (AMOC) is also investigated in an idealised climate model and the CMIP6 models. For the carbon–concentration feedback, the Atlantic, Pacific and Southern oceans provide comparable contributions when estimated in terms of the volume-integrated carbon storage. This large contribution from the Atlantic Ocean relative to its size is due to strong local physical ventilation and an influx of carbon transported from the Southern Ocean. The Southern Ocean has large anthropogenic carbon uptake from the atmosphere, but its contribution to the carbon storage is relatively small due to large carbon transport to the other basins. For the carbon–climate feedback estimated in terms of carbon storage, the Atlantic and Arctic oceans provide the largest contributions relative to their size. In the Atlantic, this large contribution is primarily due to climate change acting to reduce the physical ventilation. In the Arctic, this large contribution is associated with a large warming per unit volume. The Southern Ocean provides a relatively small contribution to the carbon–climate feedback, due to competition between the climate effects of a decrease in solubility and physical ventilation and an increase in accumulation of regenerated carbon. The more poorly ventilated Indo-Pacific Ocean provides a small contribution to the carbon cycle feedbacks relative to its size. In the Atlantic Ocean, the carbon cycle feedbacks strongly depend on the AMOC strength and its weakening with warming. In the Arctic, there is a moderate correlation between the AMOC weakening and the carbon–climate feedback that is related to changes in carbonate chemistry. In the Pacific, Indian and Southern oceans, there is no clear correlation between the AMOC and the carbon cycle feedbacks, suggesting that other processes control the ocean ventilation and carbon storage there.

中文翻译：

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CMIP6模型中的海洋碳循环反馈：来自不同盆地的贡献

海洋对碳排放的反应涉及大气中CO ₂含量增加的综合影响，其作用是增强海洋的碳储量和气候变化，以减少海洋的碳储量。这种海洋反应可以用碳浓度反馈和碳气候反馈来表征。使用11个CMIP6地球系统模型中的海洋碳酸盐化学，物理通风和生物过程的诊断方法，探索了不同洋流盆地对百年时间尺度上这些反馈的贡献。为了获得机械方面的见识，还在理想化的气候模型和CMIP6模型中研究了这些反馈对大西洋子午倾覆环流（AMOC）的依赖性。对于碳浓度反馈，按体积综合碳储量估算时，大西洋，太平洋和南部海洋提供了可比的贡献。大西洋相对其面积的巨大贡献是由于强大的局部物理通风和从南大洋输送来的碳的涌入。南大洋从大气中吸收了大量的人为碳，但是由于向其他盆地的大量碳迁移，其对碳存储的贡献相对较小。对于根据碳储量估算的碳气候反馈，相对于其规模，大西洋和北冰洋的贡献最大。在大西洋，这一巨大贡献主要是由于气候变化减少了人身通风。在北极，这种巨大贡献与单位体积的大幅度变暖有关。南大洋对碳-气候反馈的贡献相对较小，由于溶解度降低和物理通风的气候效应之间的竞争以及再生碳积累的增加之间的竞争。通风较差的印度洋-太平洋相对于其大小，对碳循环反馈的贡献很小。在大西洋中，碳循环反馈强烈依赖于AMOC强度及其随着变暖而减弱的趋势。在北极，AMOC减弱与碳酸盐化学变化相关的碳气候反馈之间存在适度的相关性。在太平洋，印度洋和南部海洋中，AMOC与碳循环反馈之间没有明显的相关性，这表明其他过程控制着那里的海洋通风和碳储存。