C波段与S波段天气雷达对冰雹天气观测的对比分析

论文总字数：10970字

目 录

1引言 5

2 雷达观测原理介绍 5

3 雷达数据与研究方法 5

4 结果与讨论 7

4.1 水平剖面的极化冰雹信号 7

4.1.1巨型冰雹 7

4.1.2大型冰雹 8

4.2垂直剖面中的冰雹特征 9

4.3 不同冰雹大小的极化雷达参量的垂直廓线 10

5 结论 12

参考文献 14

致谢 15

C波段与S波段天气雷达对冰雹天气观测的对比分析

刘金龙

Abstract: This study mainly compares and analyzes the observation results of C-band and S-band weather radars for the same strong convective weather. Because the domestic C-band and S-band have less data for the same strong convective weather, the study cited foreign relevant meteorological data for mapping and data analysis. The study was aimed at a severe hail event in Oklahoma, USA. The study was conducted by analyzing the data collected by two polar-weather radars located in the S and C bands at the same time. The polarization radar variable measured in the presence of hail in the C-band is significantly different from the polarization variable in the S-band because the resonance scattering effect is more pronounced and the attenuation effect is greater. This difference is particularly strong when melting hailstones below the freezing point, but even at higher altitudes where the hail is dry or growing in wet areas, they can be quite large. Therefore, algorithms that detect and determine the size of hail in the S-band cannot be directly applied to the C-band. The differences in the vertical distribution of the radar reflectivity Z, the differential reflectivity ZDR, and the correlation number ρhv have been studied. It shows that in the presence of hail, ZDR(C) is generally higher than ZDR(S) .In polarized hail detection/measurement, the height of the radar resolution relative to the freezing point level must be taken into account. This also indicates that the giant hailstone is usually associated with the apparent depression of ρhv in the hail occurrence area above the freezing level, while the corresponding decrease in the C-band ρhv is much larger than the S-band.

Keywords: S-band radar; C-band radar; hail; echo intensity;

1引言

冰雹灾害是强对流天气系统造成的严重气象灾害。 它通常能够对自然和人类社会造成非常严重的破坏，并且常伴有阵风和恶劣的天气过程，如强风，强降水和急速降温。雹暴主要发生在中纬度的大陆地区，通常比沿海地区的平原多，内陆多。中国的冰雹多发生在春，夏，秋季，约占四，七月份总冰雹的70％。 甘肃省西部，甘肃省，阴山山脉，太行山区，川渝县等是较为严重的抗灾区。 中国是冰雹灾害频发的国家。因此，我们有必要了解冰雹的危害，以更好地预防冰雹灾害，减少经济损失。近年来，各地为了及时、准确地监测冰雹云发展，为防雹作业提供预警、预报， 纷纷采用了卫星观测，天气雷达等多种手段对冰雹云进行监测识别，使防灾作业取得了一定成效。

截至2016年底，全国已经完成233部新一代天气雷达建设；中国气象局统筹建设的的X波段天气雷达共有42部，由地方自主建设的X波段天气雷达约200部；完成3部天气雷达的双偏振升级改造；共有69部风廓线雷达投入组网运行；天气雷达近地面1公里的覆盖范围约220万平方公里。中央气象局近日印发的《气象雷达发展专项规划（2017-2020年）规划》提出，到2020年，全国新一代天气雷达网将进一步优化完善，其中东部和东南沿海的关键区域基本由双偏振新一代天气雷达网覆盖，并使用X波段天气雷达对新一代天气雷达网的探测盲区进行补充观测；开展新型气象雷达的技术研究、业务观测和应用试验，初步建立可持续的气象雷达发展体系。其目的在于监测天气，定量测量大尺度降水，测量三维降水云体回波强度和风场。比较相邻S波段和C波段雷达的测量一致性有助于获得更精确的回波强度值。这将提高雷达降水估算的准确性，为天气预报，防洪防汛，减灾防灾提供更好的信息。不同高度的雷达在相同仰角下观测到的回波不在同一高度，无法量化差异的大小和原因。因此，利用检测案例数据，特别是典型的天气过程数据，对同一观测区域的S波段和C波段雷达回波强度进行对比分析。找出两个观测值之间差异的范围和原因对于减少雷达回波数据的不确定性，雷达估算降雨量和预报监测具有一定的意义。由于之前国内类似的对比研究较少，因此本文主要利用国外的雷达资料以及相关研究文献，总结两种不同波段雷达在冰雹探测方面的差异，寻找更好的冰雹探测方法。

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