摘要
双偏振雷达观测到的垂直伸展至环境0℃层之上的柱状差分反射率因子增强区(即Z_(DR)≥1 dB),被称为Z_(DR)柱。Z_(DR)柱可以提供对流风暴上升气流的位置和强度信息,是分析对流风暴演变的有力工具。为了实现对Z_(DR)柱的自动识别并提供用于对流风暴预警的诊断信息,基于对流风暴的三维形态特征,使用厦门双偏振雷达观测数据设计了Z_(DR)柱识别算法,并提取Z_(DR)柱形态参数。结合地面观测资料,探索Z_(DR)柱形态参数在对流风暴定量化分析领域的应用。研究表明:(1)强风暴和非强风暴在Z_(DR)柱形态参数上存在统计学上的明显差异,这为预报员据此判别两类对流风暴提供了参考依据。当Z_(DR)柱深度达到1500 m后,至少有60%的雷达体扫个数与强风暴相关。Z_(DR)柱体积、质心高度和最大Z_(DR)值的阈值达到20 m3、500 m和3 dB时,这一比例分别达到70%、70%和50%。(2)Z_(DR)柱的演变可较好地指示对流风暴的发展过程,其形态参数的极值早于强对流天气现象出现。在连续性强对流天气过程中,Z_(DR)柱的再度发展预示着对流风暴的再次增强。(3)Z_(DR)柱对于风暴的合并与分裂过程具有预示性。在风暴合并(分裂)过程中伴有Z_(DR)柱合并(分裂)的现象,其中有57%(69%)的过程Z_(DR)柱提前于对流风暴发生合并(分裂)。(4)Z_(DR)柱的位置与对流风暴的后续传播方向存在相关,可为改善对流风暴移动路径的预测提供参考依据。
Z_(DR)column,the quasi-vertical continuous column of enhanced differential reflectivity(i.e.,Z_(DR)≥1 dB)observed by dual-polarization radar,can extend well above the environmental 0℃level.Z_(DR)column can provide information about the location and intensity of convective storm updraft,which makes it a useful tool for analyzing the evolution of convective storms.This paper introduces an automatic Z_(DR)column identification algorithm,which is designed to provide diagnostic information pertinent to convective storm warning.Based on the 3D structure characteristics of convective storms,the algorithm for Z_(DR)column identification is designed and its morphological parameters are calculated.The application of Z_(DR)column morphological parameters in quantitative analysis of convective storms is explored by using Xiamen dual polarization radar and automatic weather station data.The study yields the following results.(1)Statistically significant differences exist between severe and non-severe storms in terms of the Z_(DR)column morphological parameters,indicating that these products can provide references for forecasters to distinguish the two types of convective storms.Once the Z_(DR)column depth reaches 1500 m,at least 60%of the volume scans are associated with severe storms.Similarly,once the thresholds for Z_(DR)column volume,centroid height and maximum Z_(DR)value reach 20 m3,500 m and 3 dB,respectively,at least 70%,70%and 50%of the volume scans are associated with severe storms.(2)The evolution of Z_(DR)columns is an appropriate index that can reflect the development of convective storms,and the peak values of its morphological parameters precede the occurrence of severe convective weather.During the continuous severe convective weather process,the re-development of the Z_(DR)column is earlier than that of the convective storm.(3)Z_(DR)columns can predict the merging and splitting process of convective storms.The process of storm merging(splitting)is accompanied by the Z_(DR)column merging(splitting).Z_(DR)c
作者
潘佳文
徐鸣一
吴举秀
吴伟杰
郑秀云
彭婕
韩颂雨
PAN Jiawen;XU Mingyi;WU Juxiu;WU Weijie;ZHENG Xiuyun;PENG Jie;Han Songyu(Xiamen Key Laboratory of Straits Meteorology,Xiamen Meteorological Bureau,Xiamen 361012,China;CMA Meteorological Observation Centre,Beijing 100081,China;Key Laboratory for Meteorological Disaster Prevention and Mitigation of Shandong,Shandong Meteorological Engineering Technology Center,Jinan 250031,China;Zhejiang Meteorological Information Network Center,Hangzhou 310000,China)
出处
《气象学报》
CAS
CSCD
北大核心
2023年第6期943-957,共15页
Acta Meteorologica Sinica
基金
国家重点研发计划(2022YFC3004101)
福建省自然科学基金(2022J011080、2022J01443)
山东省自然科学基金(ZR2020MD052)
浙江省自然科学基金(LZJMY23D050006)
厦门市社会发展领域指导性项目(3502Z20214ZD4005)。
关键词
双偏振雷达
Z_(DR)
柱
识别算法
对流风暴
Dual-polarization radar
Z_(DR)column
Identification algorithm
Convective storm
