| 深圳S波段与X波段双偏振雷达在定量降水估计中的应用 |
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| 引用本文： | 张哲,戚友存,朱自伟,李东欢,曾庆锋,兰红平.深圳S波段与X波段双偏振雷达在定量降水估计中的应用[J].气象学报,2021,79(5):786-803. |
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| 作者姓名： | 张哲 戚友存 朱自伟 李东欢 曾庆锋 兰红平 |
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| 作者单位： | 1.中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室，北京，100101 |
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| 基金项目： | 国家重点研发计划项目（2018YFC1507505）、中国科学院A类战略性先导科技专项（XDA2006040101）和中国科学院百人计划项目 |
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| 摘 要： | 双偏振多普勒天气雷达的一个重要应用是进行定量降水估计（QPE），它可以获得反射率（ZH）、差分反射率（ZDR）和差传播相移率（Kdp）这些与降水粒子有关的信息，常用的双偏振雷达降水估计方法有基于ZH的R（ZH）、基于ZH和ZDR的R（ZH，ZDR）、基于Kdp的R（Kdp）和基于Kdp与ZDR的R（Kdp，ZDR）这4种。文中利用深圳市S波段和X波段双偏振多普勒雷达探测资料，结合高精度地形数据和雨滴谱仪观测数据，设计了基于双偏振量的定量降水估计方法:首先利用地形数据和雷达地理信息，分析了雷达的遮挡状况，形成了这两部雷达的复合平面扫描仰角信息；随后利用雨滴谱仪观测资料，使用T矩阵方法统计得到了深圳地区的上述4种降水反演方法的参数；最后设计了混合降水反演方法，基于双偏振信号（即Kdp和ZDR）的强弱，使用不同的降水反演方法进行定量降水估计。基于12个降水个例，利用各反演方法产生的定量降水估计结果与雨量计观测资料比较。结果表明，混合降水反演方法在降水反演的准确度和稳定性上均优于任何一种单一定量降水估计反演方法。基于文中介绍的定量降水估计方法，使用深圳S波段和X波段雷达产生了定量降水估计产品，并与深圳目前业务定量降水估计产品进行对比评估。结果表明，使用本方法产生的定量降水估计产品在准确度和稳定性上要优于目前的业务产品。此外，X波段雷达的定量降水估计产品性能要略高于S波段雷达的定量降水估计产品，这说明高时、空分辨率的X波段雷达可以提高定量降水估计精度。但由于雷达扫描平面内双偏振雷达对融化层和冰区的偏振量观测与降水的关系尚未明确，因此，本方法仅适用于雷达扫描平面内液态降水区。
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| 关 键 词： | 双偏振雷达 定量降水估计 雨滴谱 |
| 收稿时间： | 2021/2/24 0:00:00 |
| 修稿时间： | 2021/4/30 0:00:00 |
Application of radar quantitative precipitation estimation using S-band and X-band polarimetric radars in Shenzhen |
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| ZHANG Zhe,QI Youcun,ZHU Ziwei,LI Donghuan,ZENG Qingfeng,LAN Hongping.Application of radar quantitative precipitation estimation using S-band and X-band polarimetric radars in Shenzhen[J].Acta Meteorologica Sinica,2021,79(5):786-803. |
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| Authors: | ZHANG Zhe QI Youcun ZHU Ziwei LI Donghuan ZENG Qingfeng LAN Hongping |
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| Institution: | 1.Key Laboratory of Water Cycle and Related Land Surface Processes，Institute of Geographic Sciences and Natural Resources Research，Chinese Academy of Sciences，Beijing 100101，China2.University of Chinese Academy of Sciences，Beijing 100864，China3.Meteorological Bureau of Shenzhen Municipality，Shenzhen 518040，China |
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| Abstract: | One of the important application of polarimetric Doppler weather radar is quantitative precipitation estimation (QPE). Polarimetric radar detects reflectivity (ZH), differential reflectivity (ZDR) and specific differential phase (Kdp), all of which are closely related to precipitation particles. Four commonly used QPE methods include ZH-based R(ZH), ZH-ZDR-based R(ZH, ZDR), Kdp-based R(Kdp) and Kdp-ZDR-based R(Kdp, ZDR) methods. Based on the observations of Shenzhen S-band and X-band polarimetric radars as well as the high-resolution elevation data and the disdrometer data, the QPE method based on polarimetric variables is presented. First, the blockage information of the two radars is analyzed, and the hybrid tilts of the two radars are generated based on the elevation data and locations of the radars. The parameters for the above 4 QPE methods suitable for Shenzhen are then calculated with disdrometer observations using the T-matrix method. Finally, the blend method of QPE is proposed to use different QPE methods based on the intensity of polarimetric signals (i.e. Kdp and ZDR). The performance suggests the accuracy and stability of the blend method is better than any of the single QPE method. The QPE products of Shenzhen S-band and X-band radars are generated with the QPE method proposed in this paper, and their performances are evaluated against operational QPE products. Results suggest that the QPE products generated by the method proposed in this paper are better than operational products both in accuracy and stability. Besides, the performance of this method is slightly better for X-band radar than for S-band radar, suggesting that the utilization of high-resolution X-band radar can improve the accuracy of QPE. However, due to the uncertain relationship between polarimetric signals and rain rate in the melting layer and ice region in the radar scan domain, the QPE method proposed here can only be applied to liquid rainfall region of the radar scan domain. |
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| Keywords: | Polarimetric radar Quantitative precipitation estimation (QPE) Raindrop size distribution |
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