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Influence of the ocean surface velocity dependence of the wind stress on the dynamics of the Southern Ocean

风应力对海洋表面速度的依赖性对南大洋动力学的影响

基本信息

批准号：
165685330
负责人：
Professor Dr. Richard Greatbatch
金额：
--
依托单位：
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2012-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/165685330?language=en
关键词：
Influence ocean surface velocity dependence

项目摘要

The objective of the proposal is to understand the influence of the surface velocity dependence of the surface wind stress on the dynamics of the Southern Ocean. Extended Summary: The dependence of the surface wind stress on the ocean surface velocity is usually neglected in studies of the ocean on the grounds that the speed of the ocean surface current is often at least one order of magnitude smaller than that of the 10 m wind. However, recent studies have shown that including the ocean surface velocity dependence leads to a dissipative effect that is comparable in magnitude to that associated with the bottom friction in the ocean. The effect of this damping is especially strong on the mesoscale eddy field leading to a reduction of around 20% in the eddy kinetic energy in models that include the ocean surface velocity dependence compared to models that do not. In the Southern Ocean, the dynamics depend crucially on the mesoscale eddy field. In particular, a southward transport associated with the eddies is required to counter the northward Ekman transport in the surface layers due to the circumpolar westerly winds. It is the slight imbalance between these two counteracting effects that drives the meridional overturning circulation (MOC) in the Southern Ocean which, in turn, is of major importance for the global climate system, including the carbon cycle. The objective of the proposal is to understand the impact of including the ocean surface velocity in the parameterisation of the surface wind stress on the dynamics of the Southern Ocean. Since we expect to find a damping of the mesoscale eddy field, there is a need to explore the impact of this damping on the mean flow (e.g. the strength of the Circumpolar Current) and on the MOC. It has also been suggested that variations in the damping play a role in determining the variability of the eddy field in the ocean. Understanding the impact of the damping is therefore important for understanding the response of the Southern Ocean to changes in the overlying wind field and to climate change.

该提案的目的是了解表面风应力对表面速度的依赖对南大洋动力学的影响。扩展摘要：在海洋研究中，表面风应力对海洋表面速度的依赖性通常被忽略，因为海洋表面流的速度通常至少比10米风速小一个数量级。然而，最近的研究表明，包括海洋表面速度相关性在内的耗散效应在量级上可与海洋底部摩擦相关的耗散效应相媲美。与不考虑海洋表面速度依赖关系的模式相比，这种衰减对中尺度涡旋场的影响尤其强烈，导致涡动动能降低约20%。在南大洋，动力很大程度上取决于中尺度涡旋场。特别是，需要与涡旋相关的南下输送，以对抗由于绕极西风而在近地层中向北的埃克曼输送。正是这两种相互抵消作用之间的轻微不平衡驱动了南大洋的经向翻转环流(MOC)，而这反过来又对全球气候系统，包括碳循环具有重要意义。该提案的目的是了解将海洋表面速度纳入表面风应力的参数化对南大洋动态的影响。由于我们期望发现中尺度涡场的衰减，因此有必要探讨这种衰减对平均气流(例如绕极流的强度)和MOC的影响。也有人提出，在决定海洋涡旋场的可变性方面，阻尼值的变化起到了作用。因此，了解衰减的影响对于了解南大洋对上覆风场变化和气候变化的反应是重要的。