Spatial and Temporal Characteristics of Asymmetries in Tropical Cyclones
Spatial and Temporal Characteristics of Asymmetries in Tropical Cyclones
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DOI：
10.1029/2019gl083179
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发表时间：
2019-07
影响因子：
5.2
通讯作者：
Jia-Chun Guo;Z. Kuang
中科院分区：
文献类型：
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作者：
Jia-Chun Guo;Z. Kuang
方位不对称扰动对飓风很重要，因为它们可以影响飓风的路径、结构和强度。在这项工作中，我们对这些微扰的动态场和热力学场进行了时空谱分析，发现在大多数场中都有两个明显的功率峰。我们首先通过为每个模选择的频率-波数光谱窗口对场进行滤波，然后根据过滤后的雷达反射率将这些场回归到一个指数，从而获得每个模的结构。我们发现，快速传播的波以眼壁附近的扰动为主，其结构类似于不稳定的混合涡Rossby惯性重力波。另一个峰值对应于一个慢传播的波，它在眼壁内外都有类似的扰动。慢波具有逆行的固有传播速度，并且具有类似于对流耦合波的垂直结构。
Azimuthally asymmetric perturbations are important to hurricanes because they can influence the track, structure, and intensity of a hurricane. In this work, we applied space‐time spectral analysis on both dynamic and thermodynamic fields of these perturbations and found two distinct power peaks in most of the fields. We obtained the structure of each mode by first filtering the fields through a frequency‐wavenumber spectral window selected for each mode and then regressing these fields on an index based on the filtered radar reflectivity. We found that the fast‐propagating wave is dominated by perturbations near the eyewall, and its structure is similar to that of the unstable mixed vortex Rossby inertia gravity wave. The other peak corresponds to a slow‐propagating wave that has comparable perturbations in and beyond the eyewall. The slow wave has a retrograde intrinsic propagating speed and has a vertical structure that resembles that of convectively coupled waves.