Understanding the Role of Mean and Eddy Momentum Transport in the Rapid Intensification of Hurricane Irma (2017) and Hurricane Michael (2018)
Understanding the Role of Mean and Eddy Momentum Transport in the Rapid Intensification of Hurricane Irma (2017) and Hurricane Michael (2018)
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DOI：
10.3390/atmos12040492
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发表时间：
2021-04
期刊：
影响因子：
2.9
通讯作者：
Alrick Green;S. Gopalakrishnan;G. Alaka;S. Chiao
中科院分区：
文献类型：
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作者：
Alrick Green;S. Gopalakrishnan;G. Alaka;S. Chiao
热带气旋快速增强的预报是一个具有挑战性的问题。在这项研究中，对两种TC的RI过程及其影响因素进行了比较：轴对称案例（2017年的飓风Irma）和非对称案例（2018年的飓风Michael）。厄玛和迈克尔都成为对美国产生重大影响的主要飓风。飓风天气研究和预报模式（HWRF）被用来研究RI与来自大尺度环境的强迫以及随后的TC结构和对流演变之间的联系。HWRF的预报合理地再现了观测到的大尺度环境。飓风厄玛在弱到中等垂直风切变（VWS）的环境中迅速增强，这通常有利于RI，导致气旋性涡旋丰富环境中的涡旋对流云对称发展。相反，飓风迈克尔在一个对RI不利的强VWS环境中迅速增强，导致涡旋对流云的发展出现重大不对称。分析了这两个飓风的切向风动量收支，以确定RI路径的相似性和差异。结果表明，与对流过程相关的涡动输运项在RI的早期阶段对涡旋转起积极作用，在RI的后期阶段抑制旋转。在RI的早期阶段，平均运输条款表现出显着的差异，在这些TC，他们占主导地位的旋转过程中的伊尔玛和次要的旋转过程中的迈克尔。尽管有敌意的VWS，但迈克尔周围环境的有利方面似乎有助于国际扶轮的进程。
The prediction of rapid intensification (RI) in tropical cyclones (TCs) is a challenging problem. In this study, the RI process and factors contributing to it are compared for two TCs: an axis-symmetric case (Hurricane Irma, 2017) and an asymmetric case (Hurricane Michael, 2018). Both Irma and Michael became major hurricanes that made significant impacts in the United States. The Hurricane Weather Research and Forecasting (HWRF) Model was used to examine the connection between RI with forcing from the large-scale environment and the subsequent evolution of TC structure and convection. The observed large-scale environment was reasonably reproduced by HWRF forecasts. Hurricane Irma rapidly intensified in an environment with weak-to-moderate vertical wind shear (VWS), typically favorable for RI, leading to the symmetric development of vortical convective clouds in the cyclonic, vorticity-rich environment. Conversely, Hurricane Michael rapidly intensified in an environment of strong VWS, typically unfavorable for RI, leading to major asymmetries in the development of vortical convective clouds. The tangential wind momentum budget was analyzed for these two hurricanes to identify similarities and differences in the pathways to RI. Results suggest that eddy transport terms associated with convective processes positively contributed to vortex spin up in the early stages of RI and inhibited spin up in the later stages of RI in both TCs. In the early stages of RI, the mean transport terms exhibited notable differences in these TCs; they dominated the spin-up process in Irma and were of secondary importance to the spin-up process in Michael. Favorable aspects of the environment surrounding Michael appeared to aid in the RI process despite hostile VWS.