On the Extreme Rainfall Event of 7 May 2017 over the Coastal City of Guangzhou. Part I: Impacts of Urbanization and Orography
On the Extreme Rainfall Event of 7 May 2017 over the Coastal City of Guangzhou. Part I: Impacts of Urbanization and Orography
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关于2017年5月7日沿海城市广州的特大暴雨事件。第一部分：城市化和地形的影响
DOI：
10.1175/mwr-d-19-0212.1
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发表时间：
2020-02
影响因子：
3.2
通讯作者：
Jinfang Yin;Da‐Lin Zhang;Yali Luo;Ruoyun Ma
中科院分区：
文献类型：
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作者：
Jinfang Yin;Da‐Lin Zhang;Yali Luo;Ruoyun Ma
在这项研究中，使用观察性分析和18-h云渗透模拟检查了2017年5月7日，在中国南部的沿海城市广州的城市热岛（UHI）效应引起的夜间极端降雨事件。 1.33 km和底部边界条件下的结果表明，该模型在广州下游（即Huashan）上再现了对流的启动浅层中的梅索洛（Mesolow特别是，该模型分别产生最大的每小时，3和12小时的降雨量，分别为146、315和551毫米与相应的观察到的极端量相比，几乎正确的位置是184、382和542毫米。通过多普勒雷达，在半圆形上有沿着冷插座边界的上升。没有UHI效应，而没有地形的效果，UHI效应似乎直接解释了Huashan附近的对流启动和大雨，并且间接地是因为随后的Jiulong Storm的形成，而《等式》在阻止冷插座和增强凉爽的凉爽渠道方面起着重要作用。对流细胞在半圆形上持续进行对流电池的池强度，从而放大了Jiulong附近的降雨量。
In this study, a nocturnal extreme rainfall event induced by the urban heat island (UHI) effects of the coastal city of Guangzhou in South China on 7 May 2017 is examined using observational analyses and 18-h cloud-permitting simulations with the finest grid size of 1.33 km and the bottom boundary conditions nudged. Results show that the model reproduces convective initiation on Guangzhou’s downstream side (i.e., Huashan), where a shallow thermal mesolow is located, the subsequent back-building of convective cells as a larger-scale warm-moist southerly flow interacts with convectively generated cold outflows, and their eastward drifting and reorganization into a localized extreme-rain-producing storm near Jiulong under the influences of local orography. In particular, the model produces the maximum hourly, 3- and 12-hourly rainfall amounts of 146, 315, and 551 mm, respectively, at nearly the right location compared to their corresponding observed extreme amounts of 184, 382, and 542 mm. In addition, the model reproduces an intense meso-γ-scale vortex associated with the extreme-rain-producing Jiulong storm, as also captured by Doppler radar, with organized updrafts along cold outflow boundaries over a semicircle. A comparison of sensitivity and control simulations indicates that despite the occurrence of heavier rainfall amounts without the UHI effects than those without orography, the UHI effects appear to account directly for the convective initiation and heavy rainfall near Huashan, and indirectly for the subsequent formation of the Jiulong storm, while orography plays an important role in blocking cold outflows and enhancing cool pool strength for the sustained back-building of convective cells over the semicircle, thereby magnifying rainfall production near Jiulong.