Zhao Mengnan, Ponte Rui M, Penduff Thierry
Atmospheric and Environmental Research Inc., Lexington, MA, USA.
Université Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, Institut des Géosciences de l'Environnement (IGE), Grenoble, France.
Sci Adv. 2023 Jul 21;9(29):eadg0278. doi: 10.1126/sciadv.adg0278.
Intrinsic processes such as mesoscale turbulence have recently been proved as important as atmospheric variability in causing variations in ocean bottom pressure (). Intrinsic processes are also known to generate random variability on scales larger than the mesoscale through inverse energy cascades or large-scale baroclinic instability. Here, model analyses reveal a truly global-scale, intrinsic mode of variability at monthly time scales that relies on a different mechanism. The intrinsic mode has largest amplitudes around Drake Passage and opposite polarity between the Southern Ocean and Atlantic/Arctic oceans. Its signature is consistent with localized eddy-driven anomalies of opposite sign near Drake Passage that then adjust freely in the rest of the ocean via barotropic wave processes. This intrinsic mode seems consistent with observed variability.
诸如中尺度湍流等内在过程最近已被证明在引起海底压力变化方面与大气变化同样重要。内在过程还通过能量逆向级联或大尺度斜压不稳定在大于中尺度的尺度上产生随机变化。在此，模型分析揭示了一种在月时间尺度上真正的全球尺度内在变化模式，其依赖于一种不同的机制。这种内在模式在德雷克海峡周围具有最大振幅，并且在南大洋与大西洋/北冰洋之间具有相反的极性。其特征与德雷克海峡附近正负号相反的局部涡旋驱动异常一致，这些异常随后通过正压波过程在海洋的其余部分自由调整。这种内在模式似乎与观测到的变化一致。
