| 摘要: |
| 本文利用南海海洋再分析产品REDOS（Reanalysis Dataset of the South China Sea）和风场资料CCMP（Cross-Calibrated，Multi-Platform），从能量学角度探讨了1992-2011年夏季（6-9月）越南离岸流区域涡-流相互作用特征，并通过能量收支方程诊断评估了风应力、压力梯度、正压不稳定以及平流的相对贡献。以越南离岸流的强度作为分类标准，对1992-2011年划分为正异常年、负异常年和正常年。结果表明，在正异常年，涡动能EKE（Eddy Kinetic Energy）和涡势能EPE（Eddy available Potential Energy）极大值主要分布在越南离岸流附近；在负异常年，EKE极大值向南北两侧分散，EPE极大值向北延伸；在正常年，EKE和EPE的极值空间分布介于正负异常之间。斜压不稳定是EPE年际变化的主要因素，越南离岸流影响周围海域的速度和密度分布，是斜压不稳定的主要原因。而影响EKE年际变化的因素较为复杂，压力做功是最主要的影响因素，风应力做功和平流做功次之，正压不稳定最小，其中正压不稳定依赖于流速大小和由风应力旋度扰动引起的上层水平流速剪切。 |
| 关键词: 越南离岸流 能量学分析 涡-流相互作用 年际变化 |
| DOI：10.11693/hyhz20170400086 |
| 分类号: |
| 基金项目:中国科学院战略性先导科技专项（A类）项目，XDA11010302号；国家自然科学基金项目，41576012号，41628601号，41606030号；广州市科技计划珠江科技新星专项项目，201610010148号；热带海洋环境国家重点实验室（中国科学院南海海洋研究所）自主研究项目，LTOZZ1601号，KLOCW1604号；广东省自然科学基金项目，2016A030310015号。 |
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| CHARACTERISTICS OF EDDY-MEAN FLOW INTERACTION IN THE OFFSHORE CURRENT AREA OF WESTERN SOUTH CHINA SEA |
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LI Han1,2, WANG Qiang1, HUANG Ke1, LIU Qin-Yan1, TILAK Priyadarshana3, GUAN Yu-Ping1, WANG Dong-Xiao1
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1.State Key Laboratory of Tropical Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;2.University of Chinese Academy of Sciences, Beijing 100049, China;3.Faculty of Fisheries and Marine Sciences & Technology University of Ruhuna, Matara, Sri Lanka
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| Abstract: |
| In the view of energy, the interannual variability of eddy-mean flow interaction around the Vietnam Offshore Current (VOC) in summer (June-September) from 1992 to 2011 was investigated by use of the REDOS (Reanalysis Dataset of the South China Sea) and the CCMP (Cross-Calibrated, Multi-Platform) ocean surface wind. The relative importance of wind stress, pressure gradient, barotropic instability, and advection were analyzed in energy budget. Three types of years during 1992-2011 could be recognized relative to the VOC intensity:positive KE anomaly years, negative KE anomaly years, and normal years. Results show that in the positive KE anomalous years, the peak of Eddy Kinetic Energy (EKE) and the Eddy available Potential Energy (EPE) are mainly distributed along the VOC; in the negative KE anomalous years, the peak of EKE dispersed to the north and south sides, with a northward EPE extension; in the normal years, the spatial distributions of peak EKE and EPE range between the positive and negative KE anomalies. The baroclinic instability is the main reason of the EPE interannual variability. The VOC affects the distributions of velocity and density of surrounding areas, and hence results in the baroclinic instability. However, factors are quite complicated for EKE interannual change, of which pressure work is the most important factor, wind stress work and advection are the secondary, and the barotropic instability is the least. The barotropic instability depends on the velocity of flow and the upper horizontal velocity shear caused by wind stress curl disturbance. |
| Key words: Vietnam Offshore Current energy budget eddy-flow interaction interannual variability |
