Variability and Feedbacks in the Atlantic Freshwater Budget of CMIP5 Models With Reference to Atlantic Meridional Overturning Circulation Stability
Variability and Feedbacks in the Atlantic Freshwater Budget of CMIP5 Models With Reference to Atlantic Meridional Overturning Circulation Stability
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DOI：
10.3389/fmars.2022.830821
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
K. Haines;D. Ferreira;D. Mignac
中科院分区：
文献类型：
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作者：
K. Haines;D. Ferreira;D. Mignac
有人建议，淡水运输的大西洋经向翻转环流（AMOC）在南大西洋可能是一个有用的度量确定的AMOC的稳定性，因为它可以导致反馈到北大西洋盐度，因此深水形成。在这篇手稿中，我们调查南大西洋淡水运输，淡水含量和AMOC运输的贡献在不同的大西洋纬度之间的反馈，并在不同的时间尺度在百年运行的10个CMIP 5气候模式，与北向和南向AMOC淡水运输在南大西洋。在所有模式中，盐度变化在确定南大西洋淡水输送方面比AMOC变化更重要，特别是在>10年的较长时间尺度上。只有在北大西洋，AMOC变化在改变经向淡水输送方面变得重要，这可能会导致具有稳定性影响的反馈。淡水含量的封闭预算表明，南大西洋输送只影响当地的淡水预算（在10°纬度范围内），南大西洋环流的水平输送变化在所有模式和时间尺度中总是主导翻转输送。这些结果表明，南大西洋淡水运输的AMOC是极不可能是一个有用的度量在确定AMOC稳定性的三角洲淡水运输是少得多的非连续性比AMOC环流本身在所有10 CMIP 5模型研究。
It has been suggested that freshwater transports by the Atlantic Meridional Overturning Circulation (AMOC) in the South Atlantic may be a useful metric for determining the stability of the AMOC because it can lead to feedbacks onto North Atlantic salinities and hence deep water formation. In this manuscript we investigate feedbacks between South Atlantic Freshwater transports, Freshwater content and AMOC transport contributions across different Atlantic latitudes, and at different timescales in centennial runs of 10 CMIP5 climate models, with both northward and southward AMOC freshwater transports in the South Atlantic. In all models, salinity variations are more important than AMOC variations in determining South Atlantic freshwater transports, especially on longer timescales >10 years. Only in the North Atlantic do AMOC variations become important in changing the meridional freshwater transports, which might then lead to feedbacks with stability implications. Closed budgets of Freshwater content show that South Atlantic transports only influence local freshwater budgets (within ∼10° latitude) and that variations in horizontal transports by the South Atlantic gyre always dominate the overturning transports in all models and timescales. These results suggest that South Atlantic freshwater transports by the AMOC is highly unlikely to be a useful metric in determining AMOC stability as meridional freshwater transports are much less meridionally coherent than the AMOC circulation itself in all 10 CMIP5 models studied.