1. Numerical Simulation of Vertical Heat Flux Induced by Near‐Inertial Waves With the Modulation of Mesoscale Eddy
关键词Tags: vertical structure vertical structure
摘要：最近的现场观测表明，台风引起的近惯性运动为从上层海洋到内部的热通量提供了一条有效的路径，该路径受到中尺度涡流的显着调节。然而，由于观测数据有限，驱动这一过程的动力学尚不清楚。在这项研究中，高分辨率区域海洋建模系统（ROMS）模拟用于明确解析垂直速度并分解完整的热量收支，从而能够定量分离平流和扩散的贡献。数值模型呈现了台风海马（2014）在南海引发的近惯性波（NIW）的情景，台风路径上存在两个特定涡流，一个气旋涡流（CE）和一个反气旋涡流（ACE）。 台风通过后，两个涡流中都出现带状近惯性流，并伴随着理查森数的减少，表明剪切驱动的不稳定性增强。频谱分析显示，在局部惯性频率附近有一个明显的能量峰值，近惯性动能在 ACE 中穿透更深，持续时间更长。热预算诊断进一步显示台风后垂直混合加剧，ACE 的特点是响应更强、更深。一致地，惯性带中的垂直热通量在 ACE 中比在 CE 中增强并延伸得更深，这意味着在反气旋条件下向下的热量重新分配更有效。这些结果凸显了中尺度涡流在调节台风引起的近惯性热传输的穿透深度和效率方面的关键作用。
Abstract: Recent in situ observations reveal that typhoon‐induced near‐inertial motions provide an efficient pathway for heat flux from the upper ocean into the interior, which is significantly modulated by mesoscale eddies. However, the dynamics driving the process is not well understood due to the limited observational data. In this study, a high‐resolution Regional Ocean Modeling System (ROMS) simulation is used to explicitly resolve vertical velocity and to decompose the full heat budget, enabling a quantitative separation of advective and diffusive contributions. The scenario that the near‐inertial waves (NIWs) triggered by Typhoon Kalmaegi (2014) in the South China Sea with the presence of two specific eddies along the typhoon track, one cyclonic eddy (CE) and one anticyclonic eddy (ACE) is presented by the numerical model. Following the typhoon passage, banded near‐inertial currents develop in both eddies and are accompanied by reduced Richardson numbers, indicating enhanced shear‐driven instability. Spectral analyses reveal a pronounced energy peak near the local inertial frequency with near‐inertial kinetic energy penetrating deeper and persisting longer in the ACE. Heat budget diagnostics further show intensified post‐typhoon vertical mixing, with the ACE characterized by a stronger and deeper‐reaching response. Consistently, the vertical heat flux in the inertial band is enhanced and extends deeper in the ACE than in the CE, implying more efficient downward heat redistribution under anticyclonic conditions. These results highlight the critical role of mesoscale eddies in regulating the penetration depth and efficiency of typhoon‐induced near‐inertial heat transport.