| 摘要: |
| 中南半岛近海偶极子结构是指在夏季与越南离岸流伴生的一对中尺度涡现象，其中气旋涡位于离岸流北侧，反气旋涡位于离岸流南侧，偶极子结构对于中南半岛近海水文要素具有重要影响。本文基于卫星高度计数据和HYCOM海洋模式的模拟结果，以2012年为例研究了该偶极子的演变过程，结果表明：偶极子结构7月出现，9月初鼎盛，10月消失；鼎盛时，两个涡旋直径均大于300km，在温跃层引起的最大位温异常可达±5℃。垂向结构上，反气旋涡呈中心对称，而气旋涡有非对称性，且影响深度大于反气旋涡。在200m以下，气旋涡有随深度增加向东倾斜的趋势，而反气旋涡有随深度增加向西偏移的趋势，但该趋势在200m层以上并不显著。对偶极子涡旋区域进行能量分析，结果表明偶极子能量主要来自于越南离岸流提供的正压和斜压能量，即越南离岸流区域是偶极子结构的主要能量源，局地风场对偶极子结构的维持也具有重要作用。能量既可以由离岸流输送给涡旋，也可以从涡旋向离岸流转化，但总体上是离岸流向涡旋提供能量。 |
| 关键词: 中尺度涡 偶极子结构 越南离岸流 风应力旋度 |
| DOI：10.11693/hyhz20200100003 |
| 分类号:P731 |
| 基金项目:国家重点研发计划“海洋仪器设备规范化海上试验”，2016YFC1401300号。 |
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| LIFE CYCLE OF MESOSCALE DIPOLE STRUCTURE NEAR THE COAST OF INDO-CHIAN PENINSULA |
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QIU Shi, CHEN Xue-En, TANG Sheng-Quan
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College of Oceanic and Atmospheric Sciences, Ocean university of China, Qingdao 266100, China
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| Abstract: |
| A dipole structure is an anticyclonic eddy and a cyclonic eddy located in the south and north of the Vietnam offshore current (VOC) in summer, respectively, and it has an important impact on the surrounding hydrologic features. Based on the HYCOM model data and satellite altimeter merged data, the life cycle of the mesoscale eddies in 2012 is reproduced, revealing that the dipole structure appears in July, peaks in early September, and disappears in October. The diameters of these mesoscale eddies are more than 300 km, and they may induce ±5℃ potential temperature anomalies in thermocline layer. In terms of vertical structure, the anticyclonic eddy is centrosymmetric while the cyclonic eddy is asymmetric with a stronger impact under the thermocline. Beneath the 200m layer, the cyclonic eddy tends to decline eastward (offshore), while the anticyclonic eddy tends to deflect westward (near-shore) with deepen depth. However, this tendency is not obvious in the upper ocean. Energy analysis shows that the main energy source region of dipole structure is from the VOC, which provides baroclinic and barotropic energy, and the local wind fields is also important in the maintenance of the dipole structure. Energy can be transported from the VOC to the dipole structure and vice versa, but the energy provider in the mass is the VOC. |
| Key words: mesoscale eddies dipole structure Vitenam Offshore Current (VOC) wind stress curl |
