| LIU Zhiliang,PANG Chongguang. 2017. The Rhines effect on the geographical characteristics of altimeter-observed eddies. Acta Oceanologica Sinica, 36(9):10-14 |
| The Rhines effect on the geographical characteristics of altimeter-observed eddies |
| Rhines效应对高度计观测的海洋中尺度涡空间分布特征的影响 |
| Received:February 13, 2017 |
| DOI:10.1007/s13131-017-1105-0 |
| Key words:Rhines effect mesoscale eddy Rossby wave energy cascade eddy desert |
| 中文关键词: Rhines效应 中尺度涡 Rossby波 能量串级 涡旋沙漠 |
| 基金项目:The National Natural Science Foundation of China under contract No. 41276026; the Ocean Strategic Pilot Project of Chinese Academy of Sciences under contract No. XDA11020301; the Key Program of National Natural Science Foundation of China under contract No. 61233013. |
| Author Name | Affiliation | E-mail | | LIU Zhiliang | Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China | zhlliu@qdio.ac.cn | | PANG Chongguang | Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China | |
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| Abstract: |
| The Rhines effect may be regarded as an interaction between Rossby waves and turbulence, in which the Rossby waves may radiate away eddy energy when their frequencies are equal or larger than those of the turbulence, thereby deforming and eventually destroying the existing eddies. Through comparing eddy-scale velocity and long Rossby wave phase speed in the oceans, a generalized form of the Rhines effect is examined on the geographical characteristics of altimeter-observed eddies. The results show that the generalized Rhines effect has a much greater influence on eddy characteristics than its classical form, which only considers the simple beta effect due to the meridional gradient of planetary vorticity. The largest amount of eddies are detected in regions where eddy-scale velocity is larger than the critical Rossby-wave phase speed considering a generalized beta effect. The eddies in those regions can grow via an inverse kinetic energy cascade and have much larger amplitudes and sizes. The "eddy desert" regions outside of the tropical oceans, which have far fewer detected eddies and much weaker eddy amplitudes, lie in areas where the eddy-scale velocity is less than the critical Rossby-wave phase speed. In those regions, the generalized Rhines effect may be a possible mechanism of suppressing eddy growth. |
| 中文摘要: |
| Rhines效应是指Rossby波和大湍流(中尺度涡)相互作用,将涡动能量以波的形式传播出去,从而使中尺度涡发生形变,最终消亡的一种动力学机制。本文通过比较海洋里涡特征速度和Rossby长波波速的方法,研究了一种广义的Rhines效应对高度计观测的海洋中尺度涡空间分布特征的影响。结果显示,广义Rhines效应比只考虑行星涡度梯度的传统形式对中尺度涡的分布具有更显著的影响。大部分中尺度涡分布在涡特征速度(Ue)大于由广义Beta值计算的Rossby长波波速(Ucg)的区域。这些涡可以由动能反向串级过程获取能量,成长为振幅和空间尺度较大的涡。热带海域以外的“涡旋沙漠”区域,中尺度涡的数量稀少,强度很弱,大都分布于Uecg的海域。广义Rhines效应可能是这些海域中尺度涡难以成长的动力学机制。 |
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