吕宋海峡黑潮与中尺度涡相互作用的能量与涡度收支分析

Kuroshio in the Luzon Strait as a strong atypical (gap-leaping) Western Boundary Current, interacts with nonlinear meso-scale eddies nearby, during which process the energy and vorticity budgets of the system is an important and insufficiently studied scientific issue. It involves three important physical processes: (1) Where does the meso-scale eddy energy propagating from the North Pacific interior ultimately go? (2) Would meso-scale eddies interacting with Kuroshio supply considerable eddy-viscosity or eddy-forcing that slightly modifies the vorticity balance to aid Kuroshio’s leaping over Luzon Strait? (3) Is the process of eddy shedding from Kuroshio bend, which significantly influences the Northern South China Sea dynamic environment, closely connected with eddy–flow interaction? This project is proposed to diagnose the energy and vorticity budgets of Kuroshio-eddy interaction process in the Luzon Strait, and to figure out the generation, dissipation, as well as non-local transport of eddy energy. Appling “Muti-Scale Energy and Vorticity Analysis” (MS-EVA) method to the typical process of anti-cyclonic eddy shedding from Kuroshio bend, we are going to study the evolution of energy transfer between mean-flow and eddy. The mechanism of eddy feedback to Kuroshio will also be studied, such as eddy-viscosity or eddy-forcing effect that might modifies the vorticity balance to aid Kuroshio’s leaping over Luzon Strait. By numerically simulating the interaction of Kuroshio and a single isolated vortex (cyclonic or anti-cyclonic), we will analyze the asymmetry between the cyclonic and anti-cyclonic cases, which would help to promote our understanding of the strong nonlinear eddy-flow interactions.

吕宋海峡黑潮作为非典型（豁口）强西边界流，在与非线性中尺度涡相互作用过程中，系统的能量和涡度收支是一个重要而未经充分研究的科学问题，它涉及到三个重要物理过程：(1)从大洋内区汇集而来的中尺度涡能量去向哪里；(2)中尺度涡与黑潮相互作用能否提供可观的涡粘性或者涡强迫效应，对黑潮跃过吕宋海峡的涡度平衡有辅助效应；(3)显著影响南海北部动力环境的黑潮脱落反气旋涡过程与涡-流相互作用有何关系。本项目拟对吕宋海峡涡-流相互作用过程进行能量和涡度收支诊断，给出吕宋海峡附近中尺度涡能量的局地生成、耗散和空间输运特征；通过“多尺度能量涡度分析方法”(MS-EVA)研究黑潮脱落反气旋涡这一典型过程中，涡-流之间能量转化的发展演变特征；分析中尺度涡对平均流的涡粘性或者涡强迫等反馈作用；模拟黑潮与单个气旋或反气旋涡相互作用过程，分析气旋和反气旋涡与黑潮相互作用的不对称性，为理解涡-流强非线性相互作用提供参考依据