Revisit the Vertical Structure of the Eddies and Eddy-Induced Transport in the Leeuwin Current System
Revisit the Vertical Structure of the Eddies and Eddy-Induced Transport in the Leeuwin Current System
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重新审视卢文洋流系统中涡流的垂直结构和涡流引起的输运
DOI：
10.1029/2020jc016556
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发表时间：
2021-04-01
影响因子：
3.6
通讯作者：
Cai, Shuqun
中科院分区：
文献类型：
--
作者：
He, Yinghui;Feng, Ming;Cai, Shuqun
陆温流系统中涡旋的垂直结构影响着涡旋体积、热量和盐分的输送，甚至影响着生态系统。然而，这里的涡动垂直结构和涡动诱导输送的理解仍然非常有限。在这项研究中，卫星观测到的海面高度与长达十年的Argo浮标的原位测量相结合，研究LC系统中尺度涡旋的垂直结构及其体积，热量和盐的传输。本文提出了一种新的涡结构重建方法，该方法考虑了涡和背景流的影响，可用于研究涡的三维结构。结果表明，在LC系统中，反气旋性涡旋（AE）通常是表层增强的，在混合层以下地转速度急剧减小，而气旋性涡旋（CE）则是次表层增强的，最大速度出现在240 m处。平均AE（CE）的密度异常核心位于130 m（650 m）深度处，密度异常为-0.51（0.24）kg/m（3）。平均CE的体积积分涡动动能和有效位能远大于平均AE的体积积分涡动动能和有效位能。CE的平均寿命明显长于AE，这可以通过CE的更深的垂直尺度来解释。沿海（东经107度）部分通过涡流漂移产生的海上体积输送为9.05 Sv（12.5 Sv）。通过涡流漂移穿过海岸（107 ° E）部分的热量和盐向陆地输送分别为10.6 Tw和143.1吨/秒（17.1 Tw和241.0吨/秒）。
The vertical structure of eddies in the Leeuwin Current system affects the eddy volume, heat, and salt transport, even the ecosystem. However, the understanding of eddy vertical structure and eddy-induced transport here are still very limited. In this study, satellite observed sea surface heights were combined with decade-long in situ measurements of Argo floats to study the vertical structure of mesoscale eddies in the LC system and their volume, heat, and salt transport. A novel eddy reconstruction method, which considers the influences of both the eddy and background flow, is devised to study the three-dimensional structure of eddies. Result shows that, in LC system, anticyclonic eddies (AEs) are usually surface-intensified, with the geostrophic velocity decreasing sharply below the mixed layer, while cyclonic eddies (CEs) are subsurface-intensified, with a maximum speed at 240 m. The density anomaly core of the average AE (CE) is at a depth of 130 m (650 m) with a density anomaly of -0.51 (0.24) kg/m(3). The volume-integrated eddy kinetic energy and available potential energy of the average CE are much larger than those of the average AE. The average lifespan of CEs is significantly longer than that of AEs, which can be explained by the deeper vertical scale of CEs. The offshore volume transport by eddy drift across the coastal (107 degrees E) section is 9.05 Sv (12.5 Sv). The heat and salt onshore transport by eddy drift across the coastal (107 degrees E) section are, respectively, 10.6 Tw and 143.1 ton/s (17.1 Tw and 241.0 ton/s).