季风和中尺度涡旋对吕宋海峡黑潮路径迟滞变异过程的影响

The path variation of the Kuroshio at Luzon Strait plays an important role in the water transition between the South China Sea and North Pacific Ocean, also has great impact on the climate change of China. Because of strong nonlinearity character and lacking of long term continuous observation,the regularity and mechanism of variation of the Kuroshio path is still unknown. After application of the nonlinear dynamical theory, people gradually realize the variation of the Kuroshio path at Luzon Strait has multiple steady states and exists hysteresis process.This proposal is based on nonlinear dynamical theory, using 1.5 layer reduced gravity shallow water equation model and real boundary condition, to study the effect and mechanism of monsoon and mesoscale eddies on the path transition of the Kuroshio at Luzon Strait.The aim is to reveal the relationship between the monsoon ( direction, domain,strength and duration) and mesoscale eddies (pattern, radius, strength and position) with the intrusion of the Kuroshio at Luzon Strait. The practical applicability of this theory is also tested and verified by comparing with the observation data.These research results will help us to further understand the regularity and mechanism of path transition of the Kuroshio, also provide a basic theory and new direction of forecasting the intrusion of the Kuroshio.

吕宋海峡黑潮路径的变异对我国南海与西北太平洋水交换以及我国气候变化具有重要影响。由于该海域存在强烈的非线性特征并缺乏长时间序列的连续观测，人们对此处黑潮路径变异的规律及其机制仍不清楚。自该区域黑潮的研究引入非线性动力系统理论方法后，人们逐渐认识到该处黑潮路径的变异存在多平衡态和迟滞过程。本项目正是基于该非线性动力系统理论，采用1.5层约化重力浅水方程模式和实际海陆边界条件，研究季风和中尺度涡旋对吕宋海峡黑潮路径迟滞变异过程的影响及其动力机制，揭示季风（风向，范围，强度，持续时间等）和中尺度涡旋（类型，半径，强度，位置等）与吕宋海峡黑潮入侵南海的关系，并通过与实测资料的比对来验证该理论的实用性，从而更深入的理解吕宋海峡黑潮路径变异的规律和机理，为研究黑潮入侵我国南海的可预报性提供理论基础和新的思路。

黑潮在吕宋海峡附近路径变异复杂，存在较为平直的跨越流态，也存在“南海分支”、“南海流套”和甩涡等入侵（我国南海）流态。其环流形态除与本身流量有关外，还受季风和太平洋西传的涡旋影响，因此具有显著的时空变异特征。鉴于此，本课题引入非线性动力系统理论来解释此处黑潮路径变异的动力机制。首先，确定吕宋海峡黑潮路径变异存在多平衡态和迟滞过程的参数范围，在此基础上分别研究了季风和中尺度涡旋对其路径变异的影响及其动力机制；最后结合实测资料和卫星资料，验证了该理论在吕宋海峡的实用性。该理论较为系统和全面的阐释了黑潮在吕宋海峡流态变异的主要影响因素及其动力机制，有助于我们在实际观测和研究中更好的理解其变异的多样性和不确定性。本课题还拓展的研究了双西边界流在缺口处的多平衡态及其变异机制。发现其存在入侵态，阻塞态和甩涡态，并与缺口宽度和流量有关。该结论在一定程度上解释了在苏拉威西海浮标观测到棉兰老流的气旋式大弯曲现象。