中尺度涡影响下南海近惯性能量变异特征

Near-inertial kinetic energy (NIKE) accounts nearly half of the ocean surface kinetic energy. It makes a significant contribution to maintain the strong mixing in the upper ocean, meridional overturning circulation, mixing in the deep ocean and internal waves. Previous studies showed that the mesoscale eddies have a strong influence on the propagation, evolution, and dissipation of NIKE. However, the way of influence and the dynamic mechanism under it is still unclear. The upper layer circulation of the South China Sea (SCS) is driven mainly by the east Asian monsoon. Typhoon and eddies are frequently observed in the SCS. Nevertheless, NIKE in the SCS and its variation features influenced by mesoscale eddies have not been systematic studied. By using mooring observations collected by the South China Sea Institute of Oceanology in recent years, measurements from satellite radars and data from numerical simulations, this program will investigate the basin-scale features of NIKE and its relationship with eddies. Furthermore, the budget and transport of energy between mesoscale eddies and NIKE will be diagnosed. Finally,from the perspective of dynamic and thermal effect of eddies, the processes and mechanisms about the influence by mesoscale eddies on vertical propagation of NIKE will be examined.This work will clarify the role of mesoscale eddies on the evaluation of NIKE in the SCS. It also provides important implications for the study of NIKE evolution in other regions.

近惯性动能（NIKE）几乎占到海洋表层动能的一半, 对维持上层强混合、经向翻转环流、海洋深层混合和内波等皆有重要贡献。国内外研究表明，中尺度涡对NIKE的传播、演化、耗散等皆有显著影响，但其影响方式和机理尚不明确。南海受东亚季风显著影响、涡旋、台风频发，然南海NIKE及中尺度涡诱发其变异的特征和机理尚无系统研究。本项目将结合近年来收集的大量的潜标观测资料、卫星资料和数值模式，系统阐明南海NIKE各要素特征及其与涡参数的关系；进一步，诊断分析中尺度涡对NIKE的能量转换；最后，从涡旋的动力、热力效应角度出发，研究中尺度涡影响NIKE垂向传播与变异的过程和机理。通过本项目的研究，将不仅明确中尺度涡在南海NIKE演化过程中所扮演的角色，亦为全球NIKE的传播、演化、耗散等过程和机理的研究提供重要参考。

本项目重点关注南海近惯性振荡的特征与变化，刻画中尺度涡对近惯性振荡的影响。项目通过对水文、卫星资料的收集与对比，开展诊断计算，数模研究和动力分析，揭示了南海中尺度涡的基本特征和演化规律，刻画了环流、海山和大尺度气候变化对中尺度涡生成和变异的影响；研究了南海近惯性振荡特征和激发机理，揭示了南海季风爆发、台风和全日潮皆能贡献于南海近惯性振荡，认识了南海经向翻转流的近惯性振荡特征；在前两者基础上，揭示了中尺度涡对南海障碍层季节变化的影响，刻画了中尺度涡诱导近惯性能量垂向传播、激发fD1谐波和地形罗斯贝波的过程和机理。项目发表SCI论文18篇，中文核心刊物3篇。