不同黑潮入侵路径对吕宋海峡锋面涡旋的影响及机制分析

The Kuroshio frequently intrudes into the South China Sea (SCS) through the Luzon Strait (LS), generating the Kuroshio intrusion front. Frontal eddies induced by instability usually occur in the margin of front and propagate westward into the SCS along with the Kuroshio intrusion. Three typical Kuroshio intruding paths into the SCS include Kuroshio branch in the SCS, Kuroshio Current Loop, and the Kuroshio leaps across the Luzon Strait. The Kuroshio intruding pathways could provide background circulations for the generation and evolution of frontal eddies inside the LS. Furthermore interaction between Kuroshio intrusion and complex bathymetry in the LS also has important effects on the frontal eddies. Thus, this project utilizes MODIS satellite observation and high-resolution ROMS numerical model to analyze characteristics and evolution process of the Kuroshio intrusion frontal eddies in the Luzon Strait. The effects of three different pathways of Kuroshio intrusion on frontal eddies are investigated. Furthermore, the dynamic mechanism and energy transforming mechanism are explored. The effects of complex bathymetry on the evolution process of frontal eddies are emphatically analyzed. This study helps to deepen understandings for dynamic mechanisms of the mesoscale eddies in the northeastern SCS and provide theoretical basis for the numerical modelling and forecasting of mesoscale process in the SCS.

黑潮流经吕宋海峡时常常西折入侵南海形成锋面，在锋面边缘存在着一系列由不稳定引起的锋面涡旋过程，并随黑潮入侵进入南海。黑潮通常以三种主要路径入侵南海，分别是黑潮南海分支、黑潮流套和跨隙路径（不入侵）。一方面黑潮入侵路径为吕宋海峡锋面涡旋的生成和发展提供背景环流场，另一方面吕宋海峡的复杂地形在不同黑潮路径作用下也会影响锋面涡旋的发展演变过程。因此，本项目结合高分辨率MODIS卫星遥感观测和区域海洋模式ROMS，对吕宋海峡的锋面涡旋特征和生消演变过程进行分析，深入分析三种不同黑潮入侵路径对吕宋海峡锋面涡旋的影响，探讨锋面涡旋不稳定增长的动力学和能量转换机制，并重点分析吕宋海峡复杂地形在锋面涡旋生成和发展过程中的作用。该研究有助于深化对南海东北部中尺度涡生成机制的认识，进而为南海中尺度海洋动力过程的模拟和预报提供理论基础。

黑潮流经吕宋海峡时常常西折入侵南海形成锋面，在锋面边缘存在着一系列由不稳定引起的锋面涡旋过程，并随黑潮入侵进入南海。黑潮通常以三种主要路径入侵南海，分别是黑潮南海分支、黑潮流套和跨隙路径（不入侵）。本项目结合高分辨率MODIS卫星遥感观测和区域海洋模式ROMS，首先详细分析了在不同黑潮入侵路径下吕宋海峡的锋面涡旋时空分布特征，锋面涡旋在黑潮分支路径下分布最多，跨隙路径下分布最少。此外还利用模式涡度方程和热收支方程，计算锋面涡旋生成发展过程中方程各项的时间演变、分布等，进一步分析影响锋面涡旋的动力学和能量转换机制，黑潮带来的暖平流是吕宋海峡入侵锋面涡旋形成的主要原因，来自下层冷水的垂直扩散作用起到了混合冷却作用，与表层平流作用相平衡。