Improving the extreme rainfall forecast of Typhoon Morakot (2009) by assimilating radar data from Taiwan Island and mainland China
Improving the extreme rainfall forecast of Typhoon Morakot (2009) by assimilating radar data from Taiwan Island and mainland China
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通过同化台湾岛和中国大陆的雷达数据改进台风莫拉克（2009）的极端降雨预报
DOI：
10.1007/s13351-017-6007-8
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发表时间：
2017-08
影响因子：
3.2
通讯作者：
Jou Ben Jong-Dao
中科院分区：
文献类型：
--
作者：
Bao Xuwei;Wu Dan;Lei Xiaotu;Ma Leiming;Wang Dongliang;Zhao Kun;Jou Ben Jong-Dao
本研究通过同化中国大陆和台湾岛的地基雷达数据来检验改进初始场的影响，以模拟莫拉克（2009）造成的长期和极端降雨。通过径向速度数据同化（VDA）分析的涡旋位置和后续路径与最佳路径基本一致。雷达反射率资料同化（ZDA）可以显著改善雷达探测区域内的初始湿度和莫拉克向北移动的速度。结果表明，VDA和ZDA联合应用可以较好地再现台湾海峡两岸的强降水过程。敏感性试验的基础上，发现，没有ZDA，模拟风暴经历了不切实际的向内收缩后，12小时的积分，由于低估了全球再分析中的湿度，导致低估的降雨量和覆盖范围。在没有VDA的影响下，有（无）ZDA的湿（干）初始场将产生一个更南（北）的路径，从而影响到台湾海峡两岸的降水位置。进一步发现莫拉克湿度场的改善主要是由于台湾岛雷达观测到的高值反射率（强对流）的同化，特别是在垦丁站。通过对台风粒子轨迹的分析和水汽通量散度的计算，发现同化雷达资料改善台风环流后，在后续模拟中可以从环境中吸收更多的水汽，最终对海峡两岸的极端降水做出贡献。
This study examined the impact of an improved initial field through assimilating ground-based radar data from mainland China and Taiwan Island to simulate the long-lasting and extreme rainfall caused by Morakot (2009). The vortex location and the subsequent track analyzed through the radial velocity data assimilation (VDA) are generally consistent with the best track. The initial humidity within the radar detecting region and Morakot’s northward translation speed can be significantly improved by the radar reflectivity data assimilation (ZDA). As a result, the heavy rainfall on both sides of Taiwan Strait can be reproduced with the joint application of VDA and ZDA. Based on sensitivity experiments, it was found that, without ZDA, the simulated storm underwent an unrealistic inward contraction after 12-h integration, due to underestimation of humidity in the global reanalysis, leading to underestimation of rainfall amount and coverage. Without the vortex relocation via VDA, the moister (drier) initial field with (without) ZDA will produce a more southward (northward) track, so that the rainfall location on both sides of Taiwan Strait will be affected. It was further found that the improvement in the humidity field of Morakot is mainly due to assimilation of high-value reflectivity (strong convection) observed by the radars in Taiwan Island, especially at Kenting station. By analysis of parcel trajectories and calculation of water vapor flux divergence, it was also found that the improved typhoon circulation through assimilating radar data can draw more water vapor from the environment during the subsequent simulation, eventually contributing to the extreme rainfall on both sides of Taiwan Strait.
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影响因子：
0.8
作者：
I. Lin;M. Chou;Chun‐Chieh Wu
通讯作者：
I. Lin;M. Chou;Chun‐Chieh Wu
影响因子：
3.1
作者：
T. Tsuda;T. Inoue;S. Kato;S. Fukao;D. Fritts;T. Vanzandt
通讯作者：
T. Tsuda;T. Inoue;S. Kato;S. Fukao;D. Fritts;T. Vanzandt
影响因子：
3.1
作者：
Chung‐Chieh Wang;H. Kuo;Y. Chen;H. Huang;Chao Hsuan Chung;K. Tsuboki
通讯作者：
Chung‐Chieh Wang;H. Kuo;Y. Chen;H. Huang;Chao Hsuan Chung;K. Tsuboki
影响因子：
3.2
作者：
Jing Xu;Yuqing Wang
通讯作者：
Jing Xu;Yuqing Wang
影响因子：
8
作者：
Chun‐Chieh Wu
通讯作者：
Chun‐Chieh Wu