Examining Storm Asymmetries in Hurricane Irma (2017) Using Polarimetric Radar Observations
Examining Storm Asymmetries in Hurricane Irma (2017) Using Polarimetric Radar Observations
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DOI：
10.1029/2018gl080739
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发表时间：
2018-12
影响因子：
5.2
通讯作者：
A. Didlake;M. Kumjian
中科院分区：
文献类型：
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作者：
A. Didlake;M. Kumjian
飓风厄玛（2017）的双极化雷达观测为成熟热带气旋的微物理结构提供了新的见解，这些结构可以与气旋动力学联系起来。主眼墙显示出水凝物大小排序的雷达特征，这意味着大的水滴在风暴右前方象限的持续上升运动附近落下，而较小的水滴则平流向下游。在外围雨带中，对流也倾向于在右前象限开始，而层状降水则主要出现在顺风处。对于主眼壁和外部雨带，对流开始的首选象限是一致的预期运动学不对称的热带气旋在弱环境风切变，但具有中等的平移速度。发展中的次级眼壁显示出不同的不对称性，表明在后象限有一个与强降水相关的层状到对流转变。这种转变是一致的假设动力学理论的二次眼壁形成。
Dual‐polarization radar observations of Hurricane Irma (2017) provide new insight into the microphysical structure of a mature tropical cyclone that can be tied to the cyclone dynamics. The primary eyewall exhibited a radar signature of hydrometeor size sorting, which implied that large drops fell out near persistent upward motion in the front‐right quadrant of the storm, while smaller drops were advected downstream. In the outer rainbands, convective initiation was also preferred in the front‐right quadrant, whereas stratiform precipitation was predominant downwind. For both the primary eyewall and outer rainbands, the preferred quadrant for convective initiation was consistent with the expected kinematic asymmetry of a tropical cyclone in weak environmental wind shear but with moderate translation speed. The developing secondary eyewall exhibited a different asymmetry that indicated a stratiform‐to‐convective transition associated with heavy precipitation in the rear quadrants. This transition is consistent with hypothesized dynamical theories for secondary eyewall formation.