Abstract This study examined tropical cyclones (TCs) Noul and Nepartak to demonstrate the evolutions of singular vector perturbations. Perturbations comprise eigen-solutions for dry total energy from two domains with different focuses, namely the TC itself and the background atmospheric flow in East Asia. These perturbations are usually used to construct ensemble members for the probabilistic forecasts of the TC trajectory. The horizontal shapes of the TC singular vectors were consistent with asymmetric flows with the wave number of 1 or 2, with the exception of the azimuthal circulation. Most of their vertical structures had higher amplitudes in upper layers mainly concentrated at approximately 200 − 300 hPa. Thus, the upper part of the perturbations developed first, followed by the lower part over time. This process was the opposite of that noted in background singular vector perturbations in mid-latitude East Asia. Calculations of the transient eddy total energy based on analysis data for the two storms revealed that growth occurred earlier in the upper layer than in the lower layer. The cross-sectional eddy evolution in TCs exhibited a similar process to that of singular vectors. In addition, the cross-section of the three-dimensional E-vector convergence and the zonal profiles of the E-vector component also supported the downward process in TC areas. Mid-latitude E-vector analysis indicated that upward energy propagation was consistent with previous findings.

中文翻译：

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基于奇异向量的热带气旋Noul和Nepartak扰动结构与演化

摘要 本研究考察了热带气旋 (TC) Noul 和 Nepartak，以展示奇异矢量扰动的演变。扰动包括来自具有不同焦点的两个域的干总能量的本征解，即 TC 本身和东亚的背景大气流。这些扰动通常用于为 TC 轨迹的​​概率预测构建集合成员。除方位环流外，TC奇异矢量的水平形状与波数为1或2的不对称流动一致。它们的大部分垂直结构在上层具有较高的振幅，主要集中在大约 200 - 300 hPa。因此，随着时间的推移，扰动的上部首先发展，其次是下部。这个过程与中纬度东亚背景奇异矢量扰动中所注意到的过程相反。根据两次风暴的分析数据计算的瞬态涡流总能量表明，上层比下层更早发生生长。TC 中的横截面涡演化表现出与奇异向量相似的过程。此外，三维 E 向量会聚截面和 E 向量分量的纬向剖面也支持了 TC 区的下降过程。中纬度 E 向量分析表明向上的能量传播与先前的发现一致。根据两次风暴的分析数据计算的瞬态涡流总能量表明，上层比下层更早发生生长。TC 中的横截面涡演化表现出与奇异向量相似的过程。此外，三维 E 向量会聚截面和 E 向量分量的纬向剖面也支持了 TC 区的下降过程。中纬度 E 向量分析表明向上的能量传播与先前的发现一致。根据两次风暴的分析数据计算的瞬态涡流总能量表明，上层比下层更早发生生长。TC 中的横截面涡演化表现出与奇异向量相似的过程。此外，三维 E 向量会聚截面和 E 向量分量的纬向剖面也支持了 TC 区的下降过程。中纬度 E 向量分析表明向上的能量传播与先前的发现一致。三维 E 向量会聚截面和 E 向量分量的纬向剖面也支持了 TC 区的向下过程。中纬度 E 向量分析表明向上的能量传播与先前的发现一致。三维 E 向量会聚截面和 E 向量分量的纬向剖面也支持了 TC 区的向下过程。中纬度 E 向量分析表明向上的能量传播与先前的发现一致。