菲律宾附近西边界流季节内变异特征与驱动机制

Western boudarny currents in tropical Pacific play an important role in global climate and thermohaline circulation. In recent years significant intraseasonal variability (ISV) of western boundary current (especially subthermocline current) near Philippines has been revealed by deep ocean mooring observations. Therefore, characteristics and dynamics of the ISV in the western boundary current near Philippines is one of frontier problems about western tropical Pacific ocean circulation, which is quite important for understanding western boundary current dynamics and its role in global climate change.. Based on mooring observations near Philippines and high resolution numerical simulation data, with the complementary data of satellite and Argo observations, the project will study time and spacial distributions of period, strength of ISV and the relationship of ISV between upper current and subthermocline current, and reveal the ISV charateristics. Then, combined with numerical experiments and ocean dynamics theory (eddy kinetic energy equation, ocean waves theory, etc), the project will analyze the correlation of ISV of between atmospheric forcing and the currents at different levels, study the role of atmospheric forcing and ocean process (ocean instability, ocean wave) on oceanic ISV and their contributions, and reveal dynamic processes and driven mechanism of ISV of west boundary current, which will be foundation in further studying western boundary currents in tropical Pacific and their role in climate change.

热带太平洋西边界流在全球气候和热盐环流中具有重要的作用。近几年深海潜标观测发现菲律宾附近西边界流（特别是温跃层以下海流）具有显著的季节内变异特征。因此，菲律宾附近西边界流季节内变异特征与驱动机制是热带西太平洋环流研究中的前沿问题之一，对深入认识西边界流动力学及其在气候变化中的作用具有十分重要的意义。.项目将基于菲律宾附近潜标资料和高分辨率模式数据，以卫星资料、Argo资料等作为补充，研究菲律宾附近西边界流季节内变异周期、强度等时空分布，以及上层流与温跃层以下海流季节内变异之间的关系，揭示其季节内变异特征；进而结合数值实验和理论分析（涡动能方程、海洋波动理论等），分析大气强迫与不同深度海流季节内变异之间的关系，研究大气强迫和海洋过程（海洋不稳定、海洋波动）在季节内变异中的作用及其相对贡献，揭示西边界流季节内变异动力学过程和驱动机制，为深入研究热带太平洋西边界流在气候变化中的作用奠定基础。

菲律宾附近西边界流（特别是温跃层以下海流）具有显著的季节内变异是热带西太平洋环流研究中的前沿问题之一。项目分析潜标数据、卫星数据、Argo数据等，结合数值模式和理论分析，研究了热带西太平洋中尺度涡三维结构、源地黑潮、棉兰老以东温跃层以下海流、北赤道流/潜流等季节内变化，取得了以下重要结果：（1）建立热带西太平洋中尺度涡旋的三维结构与分布；（2）揭示台湾以东黑潮和吕宋海峡黑潮具有重要的50-70天的季节内变化，可能是由吕宋海峡处的涡旋引起；（3）揭示棉兰老以东温跃层以下海流还具有显著的30-50天的季节内变化，可能与温跃层以下涡旋活动有关；（4）定量化北赤道流/北赤道潜流输运并揭示其40天的季节内变化可能与MJO有关。发表和录用研究论文5篇（其中SCI论文4篇）。本项目的研究成果对深入认识西边界流动力学及其在气候变化中的作用具有十分重要的理论意义。