| 两次强冰雹超级单体风暴双偏振特征对比 |
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| 引用本文： | 刁秀广,李芳,万夫敬.两次强冰雹超级单体风暴双偏振特征对比[J].应用气象学报,2022,33(4):414-428. |
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| 作者姓名： | 刁秀广 李芳 万夫敬 |
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| 作者单位： | 1.山东省气象防灾减灾重点实验室, 济南 250031 |
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| 摘 要： | 利用S波段双偏振天气雷达资料、探空和地面常规气象观测资料及灾情调查, 对2020年6月25日河北省蠡县和2021年7月9日山东省章丘的两次特大冰雹超级单体风暴双偏振特征进行对比。结果表明:两次超级单体风暴均发生在西北气流形势下, 章丘风暴具有较强的对流有效位能、较大的湿度和较高的湿球0℃层高度。蠡县风暴强度明显大于章丘风暴, 但差分反射率柱和比差分相移柱高度明显低于章丘风暴。蠡县风暴弱回波区上方存在深厚的强度超过65 dBZ强回波悬垂, 即悬垂的冰粒子循环增长产生较大的冰雹粒子, 大的冰雹粒子进入下降通道后, 再次产生明显增长且更加不规则, 导致更强的水平极化反射率因子和更小的相关系数。湿度的垂直分布是风暴发展强度的关键环境因素之一。蠡县超级单体风暴的产生环境非常干, 章丘超级单体风暴的产生环境相对较湿。
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| 关 键 词： | 超级单体 双偏振 差分反射率柱 比差分相移柱 差异性 |
| 收稿时间： | 2022-03-21 |
Comparative Analysis on Dual Polarization Features of Two Severe Hail Supercells |
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| Affiliation: | 1.Key Laboratory for Meteorological Disaster Prevention and Mitigation of Shandong, Jinan 2500312.Shandong Meteorological Observatory, Jinan 2500313.Jining Meteorological Bureau of Shandong, Jining 2720004.Qingdao Meteorological Bureau of Shandong, Qingdao 266003 |
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| Abstract: | Using S-band dual-polarization weather radar data, sounding and ground meteorological observations, and disaster investigation reports, the similarity and difference of dual polarization parameters between Lixian and Zhangqiu supercells with hails above 50 mm are analyzed. Lixian supercell occurred at Lixian, Heibei Province on 25 June 2020, and Zhangqiu supercell occurred at Zhangqiu, Shandong Province on 9 July 2021. The results show that two supercells occurred in similar weather pattern (northwest flow) and large vertical wind shear environmental conditions which is conducive to the generation and maintenance of supercell storms, but Zhangqiu supercell is with stronger convective effective potential energy, larger humidity, and higher wet bulb 0℃ layer height. The main similarities include obvious differential reflectivity (ZDR) arcs along the forward flank of supercell storms, ZDR rings distributed around the updraft in the middle layer, and obvious ZDR columns and specific differential phase (KDP) columns above the 0℃ level. ZDR arcs are associated with large raindrops or small melting hail particles, ZDR columns mark the location of convective updrafts as large raindrops or wet ice particles are lofted to subfreezing temperatures, and KDP columns are dominated by large concentrations of small and medium-sized raindrops or melting ice particles. The similarity of the updraft structure plays a key role in the commonness or similarity of the polarization characteristics. The main differences are stronger reflectivity factor ZH, but lower height of ZDR column and KDP column in Lixian supercell. The strong overhang echo above the weak echo area in Lixian supercell contains large hail particles generated by cumulated growth. After the overhanging large hail particles enters the descending channel, they will produce obvious growth again and become more irregular, resulting in stronger horizontal polarization reflectivity factor ZH and smaller correlation coefficient. The obvious differential attenuation signature and nonuniform beam filling are observed in low level of Lixian supercell. The differential attenuation caused a decrease in the differential reflectivity as the beam propagates through large hail cores. Nonuniform beam filling is generated by inhomogeneous filling of different hydrometeor particles in the sampling volume. Under similar weather patterns, the distribution characteristic of humidity vertical profile is one of the key environmental factors of storm intensity. Lixian supercell storm occured in very low humidity vertical distribution environment, while Zhangqiu supercell storm occured in wetter environment. |
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