Sub-mesoscale ocean vortex trains in the Luzon Strait
Sub-mesoscale ocean vortex trains in the Luzon Strait
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DOI：
10.1029/2007jc004362
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发表时间：
2008-04
影响因子：
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通讯作者：
Q. Zheng;Hui Lin;J. Meng;Xiaomin Hu;Y. Song;Yuanzhi Zhang;Chunyan Li
中科院分区：
文献类型：
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作者：
Q. Zheng;Hui Lin;J. Meng;Xiaomin Hu;Y. Song;Yuanzhi Zhang;Chunyan Li
[1]利用Argos卫星跟踪的海面漂流物轨迹数据和ENVISAT（欧洲卫星）ASAR（高级合成孔径雷达）图像，对吕宋海峡的海洋涡旋序列（OVT）进行了研究。观察到发生在巴布延岛西北部的两例病例。第一列三个气旋性涡旋出现在20° ~ 20.5°N和120° ~ 121°E的漂流物轨迹上，第二列由五对气旋-反气旋性涡旋组成，在2006年11月19日获得的ASAR图像上显示，第一个事件发生在19.5°至20.0°N和121.0°至122.0°E的上游侧。涡列轴线的总长度达到250公里左右。所有涡旋都向西北方向（北纬315°）传播。平均角速度为（2.07 ± 0.18）× 10−5 s−1。从雷达成像理论出发，建立了海洋涡旋雷达图像的理论模型，从ASAR图像特征中提取动力学参数，包括两个相邻涡旋之间的距离和两排涡旋之间的距离，（22.6 ± 1.9）km，（8.2 ± 1.2）km，最大旋转速度半径为4.70 km，涡旋旋转角速度为3 × 10−5s−1。动力学分析得出电流的平均速度为0.65 ms−1，涡旋的传播速度为0.58 ms−1。旋涡脱落速率估计为2.57 × 10−5 s−1。雷诺数估计为50至500。单个涡旋和涡旋列的Rossby数分别为O（0.4）和O（0.5），表明在吕宋海峡观测到的涡旋和涡旋列都具有亚中尺度性质。该研究还揭示了一个强海流，其平均表面流速约为0.7 ms−1，方向约为315° TN，直接从太平洋通过吕宋海峡南部流向南海。平均流速可以使用本研究中开发的方法和OVT动力学模型计算。这些信息将为研究该海域的环流系统，包括黑潮的起源提供更多的信息。
[1] This study uses the Argos satellite-tracked surface drifter trajectory data and ENVISAT (European satellite) ASAR (advanced synthetic aperture radar) images to illustrate the ocean vortex trains (OVT) in the Luzon Strait. Two cases that occurred in the northwest of Babuyan Island are observed. The first train of three cyclonic vortices showed up on drifter trajectories from 20° to 20.5°N and from 120° to 121°E, and the second, consisting of five pairs of cyclonic-anticyclonic vortices, occurred on the upstream side of the first one from 19.5° to 20.0°N and from 121.0° to 122.0°E and showed up on the ASAR images acquired on 19 November 2006. The total length of the vortex train axis reaches about 250 km. All vortices propagate northwestward (∼315° TN). The mean angular velocity is (2.07 ± 0.18) × 10−5 s−1. Theoretical models of ocean vortex radar image derived from radar imaging theories are used to extract dynamical parameters from ASAR imagery signatures, which include the distance between two consecutive vortices and that between two rows of vortices of (22.6 ± 1.9) km and (8.2 ± 1.2) km, respectively, the maximum rotational velocity radius as 4.70 km, and the vortex rotational angular velocity 3 × 10−5s−1. Dynamical analyses give the mean velocity of the current of 0.65 ms−1, and the propagation velocity of the vortex 0.58 ms−1. The vortex shedding rate is estimated as 2.57 × 10−5 s−1. The Reynolds number is estimated as 50 to 500. For the individual vortex and the vortex train, the Rossby numbers are O(0.4), and O(0.5), respectively, implying that both vortex and vortex train observed in the Luzon Strait have a sub-mesoscale nature. This study also reveals a strong current with an average surface current velocity of around 0.7 ms−1 and the direction of around 315° TN flowing directly from the Pacific to SCS passing through the southern Luzon Strait. The mean flow velocity can be calculated using methods developed in this study and OVT dynamical models. This information may provide more insight to the circulation systems in the area including the origin of Kuroshio.