Yang Yiing Jang, Chang Ming-Huei, Hsieh Chia-Ying, Chang Hung-I, Jan Sen, Wei Ching-Ling
Institute of Oceanography, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan.
Nat Commun. 2019 Apr 9;10(1):1627. doi: 10.1038/s41467-019-09574-3.
Typhoon is a major cause of multiple disasters in coastal regions of East Asia. To advance our understanding of typhoon-ocean interactions and thus to improve the typhoon forecast for the disaster mitigation, two data buoys were deployed in the western North Pacific, which captured Super Typhoon Nepartak (equivalent to Category 5) in July 2016 at distances <20 km from the typhoon's eye center. Here we demonstrate that the unprecedented dataset combined with the modeling results provide new insights into the rapid temperature drop (~1.5 °C in 4 h) and the dramatic strengthening of velocity shear in the mixed layer and below as the driving mechanism for this rapid cooling during the direct influence period of extremely strong winds. The shear instability and associated strong turbulence mixing further deepened the mixed layer to ~120 m. Our buoys also observed that inertial oscillations appeared before the direct wind influence period.
台风是东亚沿海地区多种灾害的主要成因。为了增进我们对台风与海洋相互作用的理解，从而改进用于减灾的台风预报，在北太平洋西部部署了两个数据浮标，它们在2016年7月捕捉到了超级台风妮妲（相当于五级台风），距离台风眼中心不到20公里。在此我们表明，前所未有的数据集与模拟结果相结合，为极端强风直接影响期间混合层及其以下快速降温（4小时内约1.5°C）以及速度切变急剧增强这一快速冷却的驱动机制提供了新的见解。切变不稳定性及相关的强湍流混合进一步将混合层加深至约120米。我们的浮标还观测到，在直接风影响期之前出现了惯性振荡。
