黑潮入侵东海时空特征的非线性分岔研究

The Kuroshio, which acts as a strong western boundary current, flows northward from its origin and into the East China Sea (ECS) around the northeast area of Taiwan Island. When flowing through this area, it intrudes and exchanges water with China coastal seas. The enormous energy it takes directly influences the China coastal current system. The research on spatial-temporal features of Kuroshio's intrusion into ECS has great significance for environment protection and resource development of our country. In this study we introduce nonlinear bifurcation theory into the research on variations of spatial-temporal features of this phenomenon. Through the methods of field investigation, analysis of satellite remote sensing data, and numerical modeling, we try to figure out the nonlinear spatial-temporal feature of Kuroshio's intrusion into ECS, establish a nonlinear dynamic model targeted on Kuroshio branch, find out the multiple stationary states of Kuroshio and the relation among the key parameters that control the transcritical bifurcation, and finally put forward a diagram of multiple parameters controlled nonlinear bifurcation of Kuroshio intrusion. On this basis, we will try to quantitatively describe the features and mechanism of the spatial-temporal variation of Kuroshio's intrusion into ECS, and conduct an exploratory research on its predictability through high resolution 3-dimentional numerical modeling. The products of this project would be of significance for revealing the features and mechanism of the spatial-temporal variation of Kuroshio's intrusion into ECS, and for enrichment of marine dynamics theory and research methods.

黑潮作为强西边界流，其从源地向北，沿台湾东岸北上流入东海。当黑潮流经台湾东北海域时将发生对中国近海的入侵和交换并携带能量直接影响中国近海的环流系统，因此开展黑潮入侵东海时空特征研究对我国的环境保护、资源开发等具有重要意义。本项目将非线性分岔理论引入黑潮入侵东海的时空特征变异研究中，通过现场观测、卫星遥感资料分析、数值模拟等手段，给出黑潮入侵东海的非线性时空特征，构建以黑潮分支为对象的非线性动力学模式，找到黑潮的多种流态（稳定态）以及影响流态变异的各种因素（分岔点）间的关系，给出影响黑潮入侵的多参数非线性分岔图，进而揭示黑潮入侵东海时空变异机制。在此基础上，通过构建高分辨率的三维数值模式，定量化的给出黑潮入侵东海时空变异特征和机理，探索性的开展可预测性研究。本项目的研究成果对于揭示黑潮入侵东海时空变异特征和机理，丰富海洋动力学理论和研究方法具有重要意义。

黑潮作为强西边界流，其从源地向北，沿台湾东岸北上流入东海。当黑潮流经台湾东北海域时将发生对中国近海的入侵和交换并携带能量直接影响中国近海的环流系统，因此开展黑潮入侵东海时空特征研究对我国的环境保护、资源开发等具有重要意义。本项目利用基金委开放航次成功获取台湾东北部海域站位1年的潜标观测资料，基于ROMS模式构建了东海高分辨率三维数值模型，利用潜标观测资料、卫星遥感资料、HYCOM模式再分析资料分析了黑潮入侵东海的季节变化特征，并提出了台湾东北一支西南向逆流是黑潮入侵东海的重要方式并给出了其时空变异机制，在此基础上讨论了黑潮入侵东海的非线性机制。本项目的研究成果对于揭示黑潮入侵东海时空变异特征和机理，丰富海洋动力学理论和研究方法具有重要意义。