黑潮延伸体海域典型涡旋的次中尺度特征分析*
张旭(1995—), 男, 河南省周口市人, 硕士研究生, 主要从事上层海洋次中尺度过程研究。email: |
Copy editor: 林强
收稿日期: 2020-12-26
修回日期: 2021-03-01
网络出版日期: 2021-03-03
基金资助
中国科学院基础前沿科学研究计划原始创新项目(ZDBS-LY-DQC011)
国家自然科学基金项目(92058201)
国家自然科学基金项目(41776040)
中国科学院南海生态环境工程创新研究院自主部署项目(ISEE2018PY05)
版权
Submesoscale characteristics of a typical anticyclonic mesoscale eddy in Kuroshio Extension*
Copy editor: LIN Qiang
Received date: 2020-12-26
Revised date: 2021-03-01
Online published: 2021-03-03
Supported by
Original Innovation Project of Basic Frontier Scientific Research Program of CAS(ZDBS-LY-DQC011)
National Natural Science Foundation of China(92058201)
National Natural Science Foundation of China(41776040)
Innovation Academy of South China Sea Ecology and Environmental Engineering, CAS(ISEE2018PY05)
Copyright
本文基于卫星遥感资料和高分辨率ROMS(Regional Ocean Modeling System)数值模拟结果, 对黑潮延伸体海域典型中尺度涡旋的次中尺度特征进行了探讨。卫星观测和模拟结果显示, 黑潮延伸体涡旋海域伴随着活跃的次中尺度现象。涡旋演变与多尺度能量分析结果表明, 涡旋海域次中尺度动能的强弱与涡旋海域地转流动能有着密切联系, 锋生可能是涡旋边缘次中尺度动能增强的重要机制。次中尺度现象在中尺度涡旋海域具有沿地转流方向的复杂涡丝状结构特征, 意味着涡旋边缘较强的水平浮力梯度和地转流侧向剪切为次中尺度过程形成与发展提供了有利条件。此外, 垂向结构分析表明, 次中尺度过程能引起较大的垂向速度, 最大可达100m·day-1, 该垂向速度可以影响至混合层下200m深度处, 对海洋内部的垂向物质能量交换、海—气相互作用等有着重要的影响。
张旭 , 经志友 , 郑瑞玺 , 黄小龙 , 曹海锦 . 黑潮延伸体海域典型涡旋的次中尺度特征分析*[J]. 热带海洋学报, 2021 , 40(6) : 31 -40 . DOI: 10.11978/2020152
Using satellite measurements and high-resolution ROMS simulations, we analyze submesoscale characteristics of a typical anticyclonic mesoscale eddy in the Kuroshio Extension. Both satellite observations and high-resolution simulations show obvious submesoscale phenomena in the vortex region in the Kuroshio Extension. Our analysis results show that the strength of submesoscale kinetic energy is in close connection with kinetic energy of geostrophic velocity, which means that the frontogenesis may be an important way to enhance the submesoscale kinetic energy in the eddy periphery. Our analysis of the eddy’s vertical constructure shows submesoscale process can induce strong vertical velocity, which can be up to 100 m·day-1. The strong vertical velocity can reach a depth of hundreds of meters, indicating that submesoscale process can provide an efficient way for sea surface-internal material exchanging and air-sea interactions.
Key words: mesoscale eddy; submesoscale process; front; Kuroshio Extension
图2 卫星观测的5月3日黑潮延伸体气候态SST和水平流速(箭头)(a), 以及SLA(c)和模式模拟的第21年5月3日黑潮延伸体SST、水平流速(b)及SLA(d)分布图c、d中黑色曲线为气候态平均海面高度等值线, 用以表示黑潮延伸体主轴的大致位置 Fig. 2 Spatial distributions of SSH (shading) and surface currents (vector), and SLA of the Kuroshio Extension provided by remote sensing satellite (a, c) and ROMS mode (b, d). The black contours in (c) and (d) are SSH, which indicate the location of the Kuroshio Extension axis. |
图4 涡旋发展前期(a—c)、中期(d—f)和后期(g—i)表层SKE的水平分布黑色线为涡旋外边界, 红色线为涡旋中心外边界 Fig. 4 Surface submesoscale kinetic energy distributions in early (a-c), mid (d-f), and late (g-i) development stages of the eddy. Eddy boundary and eddy core are marked by black and red curves in each panel, respectively |
图5 涡旋边缘(蓝线, 单位: 10-3m2·s-2)与涡旋中心(红线, 单位: 10-3m2·s-2)的平均次中尺度动能及涡旋边缘(绿线, 单位: 10-16s-5)与涡旋中心(紫线, 单位: 10-16s-5)锋生函数的时间演变曲线Fig. 5 Time series of SKE in eddy periphery (blue curve), eddy center (red curve), and front function in eddy periphery (green curve) and eddy center (purple curve) |
图6 模拟结果第21年5月3日涡旋海域的海表面温度、水平流速(箭头)(a)与罗斯贝数Ro(b)的水平分布a中白色线为等温线; b中黑色实线为下文所分析的37°30'N断面位置 Fig. 6 Maps of SST (a) and Ro (b) from the R2 simulation. The vectors and white contours in (a) are for surface currents and isotherms, respectively. The black line in (b) is the location of the 37°30'N section analyzed later in the paper |
图9 锋面强度(填色)及垂向次中尺度流速异常ω’(箭头)(a)、锋生函数(b)、罗斯贝数(c)和垂向浮力通量(d)的37°30'N断面分布a中灰色曲线为混合层深度(采用密度阈值法计算, σ=0.03kg·m-3); a—d中黑色竖直线为涡旋边缘与中心的分界 Fig. 9 Vertical profiles of frontal sharpness (shading), vertical velocity anomaly (black arrows) (a), front function (b), Ro (c), and bouncy flux (d). The grey curve in (a) represents the mixed-layer depth, and the black lines in each panel separate the eddy center and periphery |
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