挟带黑潮高盐水的中尺度涡在南海北部的时空特征
曾丽丽(1981—), 女, 山东省聊城市人, 研究员, 博士, 博士生导师, 从事海洋环流动力和海气相互作用研究。email: |
Copy editor: 林强
收稿日期: 2022-07-05
修回日期: 2022-09-14
网络出版日期: 2022-09-28
基金资助
南方海洋科学与工程广东省实验室(广州)专项(GML2019ZD0306)
国家自然科学基金项目(41676018)
广州市科技计划项目(202002030490)
Spatiotemporal characteristics of mesoscale eddies with transport capability of saline Kuroshio water in the northern South China Sea
Copy editor: LIN Qiang
Received date: 2022-07-05
Revised date: 2022-09-14
Online published: 2022-09-28
Supported by
Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0306)
National Natural Science Foundation of China(41676018)
Science and Technology Planning Project of Guangzhou City, China(202002030490)
吕宋海峡处涡致输运显著影响南海北部的热盐平衡。本文利用1993—2018年间的AVISO卫星数据, 识别和筛选了南海北部76个黑潮脱落反气旋涡、46个黑潮伴生气旋涡、29个南海局地反气旋涡和40个南海局地气旋涡。分析发现, 四类涡旋的平均非线性系数均远大于1, 证实了筛选涡旋具有黑潮高盐水输运能力。涡旋传播路径受南海北部地形影响, 在西向传播过程中向西南向偏移。相较于气旋涡, 反气旋涡形成之后向南海北部移动了更远的距离。涡旋多形成于吕宋海峡中部, 而随着纬度的升高或降低, 形成概率逐渐减小。脱落(伴生)涡旋多形成于秋冬两季而夏季最少, 以反气旋涡居多, 平均每月反气旋涡要比气旋涡多2.5个; 年平均脱落(伴生)涡旋数目约为4.6, 且气旋涡并不是每年都形成。整体上, El Niño事件通过影响黑潮路径而使得黑潮脱落或伴生的涡旋数目增多。
杨一凯 , 曾丽丽 . 挟带黑潮高盐水的中尺度涡在南海北部的时空特征[J]. 热带海洋学报, 2023 , 42(3) : 75 -85 . DOI: 10.11978/2022152
Eddy-induced transport in the Luzon Strait significantly affects the thermo-salt balance in the northern South China Sea. Using the AVISO satellite data from 1993 to 2018, this paper identifies and screens 76 Kuroshio shedding anticyclic eddies, 46 Kuroshio associated cyclonic eddies, 29 South China Sea (SCS) locally-formed anticyclic eddies and 40 SCS locally-formed cyclonic eddies in the northern SCS. The average nonlinear coefficients of the four types of eddies are all much larger than 1, which confirms that the screening eddies do have the capacity of transporting the saline Kuroshio water. The propagation paths of the eddy are affected by the topography of the northern SCS, and shift to the southwest during the westward propagation process. Compared with the cyclonic eddy, the anticyclonic eddy moved farther to the northern part of the SCS. The eddies are mostly formed in the middle of the Luzon Strait, and the probability of formation gradually decreases with the increase or decrease of latitude. The shedding (associated) eddies are mostly formed in autumn and winter and the least in summer and the average number of anticyclonic eddies is 2.5 more than cyclonic eddies per month. The annual average number of shedding (associated) eddies is about 4.6, and cyclonic eddies do not form every year. Overall, the El Niño event increases the number of Kuroshio shedding or associated eddies by affecting the Kuroshio path.
Key words: northern South China Sea; Kuroshio; saline water; mesoscale eddy
图1 吕宋海峡以西一个黑潮脱落反气旋涡在1993年1月1日的SSH与地转流(a)及SLA与地转流异常(b)绿色五角星代表涡旋中心, 绿色圆圈指示涡旋随后的移动路径。基于国家测绘地理信息局标准地图服务网站下载的审图号为GS(2016)1665号的标准地图制作 Fig. 1 SSH and geostrophic current (a) and SLA and geostrophic current anomaly (b) of a Kuroshio shedding anticyclonic eddy west of the Luzon Strait on January 1st, 1993. The green star represents the eddy center, and the green circle indicates the subsequent propagation path of the eddy |
表1 四类涡旋平均旋转速度、传播速度和非线性系数Tab. 1 Average rotational velocity, propagation velocity and nonlinear coefficient of four types of eddies |
参数 | 脱落反气旋涡 | 伴生气旋涡 | 局地反气旋涡 | 局地气旋涡 |
---|---|---|---|---|
平均旋转速度U/(m·s-1) | 0.38 | 0.32 | 0.34 | 0.34 |
平均传播速度c/(m·s-1) | 0.12 | 0.13 | 0.15 | 0.11 |
平均非线性系数 | 6.6 | 5.4 | 6.0 | 7.3 |
图3 筛选涡旋的标准化涡动能随标准化生命周期的演变红实线、蓝实线、红虚线和蓝虚线分别代表脱落反气旋涡、伴生气旋涡、局地反气旋涡和局地气旋涡。 Fig. 3 Evolution of normalized EKE of the screening eddies with normalized lifetime. The red solid line, blue solid line, red dashed line and blue dashed line represent shedding anticyclonic eddy, associated cyclonic eddy, locally formed anticyclonic eddy and locally formed cyclonic eddy, respectively |
图4 黑潮脱落(伴生)涡旋路径分布与沿吕宋海峡南北向的形成概率a、b为脱落反气旋涡; c、d为伴生气旋涡。黑线为涡旋移动路径; 红色和蓝色圆圈分别代表涡旋形成与消亡的位置。基于国家测绘地理信息局标准地图服务网站下载的审图号为GS(2016)1665号的标准地图制作 Fig. 4 The path distribution of associated eddy and their formation probability along the north-south direction of the Luzon Strait: (a) and (b) correspond to anticyclonic eddy, while (c) and (d) correspond to cyclonic eddy. The red and blue circles represent the location of eddy formation and extinction, respectively |
图5 南海局地涡旋路径分布与沿吕宋海峡南北向的形成概率a和b对应反气旋涡, c和d对应气旋涡。黑线为涡旋移动路径; 红色和蓝色圆圈分别代表涡旋形成与消亡的位置。基于国家测绘地理信息局标准地图服务网站下载的审图号为GS(2016)1665号的标准地图制作 Fig. 5 The path distribution of locally formed eddy and their formation probability along the north-south direction of the Luzon Strait, (a) and (b) correspond to anticyclonic eddy, while (c) and (d) correspond to cyclonic eddy. The red and blue circles represent the location of eddy formation and extinction, respectively |
图8 MEI(柱图)、KSI(橙线)与黑潮脱落(伴生)涡旋数目(绿线)的关系MEI正值指示暖的El Niño事件, 负值指示冷的La Niña事件 Fig. 8 The relationship between MEI (bar), KSI (orange line) and the number of Kuroshio shedding (associated) eddies (green line). Positive MEI values indicate the warm El Niño events and negative values indicate the cold La Niña events |
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