摘要
为了提高当地冰雹预报预警及防御能力,利用地面气象观测资料、探空和双偏振雷达资料,分析2011—2020年关中北部的冰雹个例,总结冰雹天气环境发生的参量预报预警指标和雷达识别特征。结果表明:关中北部冰雹集中发生在5—8月,且6月和7月为高发时段;具有明显日变化特征,主要发生时段为14:00—18:00。暖季降雹的不稳定条件预警指标为K指数≥25.0℃,850 hPa和500 hPa的温差≥25.3℃,沙氏指数≤-1.1℃;能量条件预警指标为对流有效位能≥562 J/kg;水汽条件预警指标为500 hPa温度露点差≥9.0℃;垂直风切变预警指标为0~6 km深层风垂直切变≥7.3 m/s或0~3 km低层风垂直切变≥4.3 m/s;特殊层高度预警指标为0℃层和-20℃层高度分别为3.4~4.0 km和7.2~8.1 km。双偏振雷达识别特征预警指标为回波强度超过53 dBz,回波顶高超过10 km,回波悬垂高度超过1.8 km,且出现三体散射长钉,长钉长度超过5.2 km;速度场上低层有辐合,辐合强度超过10.5 m/s;垂直液态水含量VIL最大值高于15 kg/m2,VIL跃增值≥10 kg/m2,VIL密度≥2.6 g/m3。双偏振雷达的差分反射率因子、差分传播相移因子、零延迟相关系数等偏振参量对冰雹相态的识别也有很好的指示意义。该指标预报准确率较高,但也存在一定的空报。
To improve the local hail forecast and natural disaster prevention,based on data from surface meteorological observation,sounding station and dual polarization radar,hail incidents in the north of Guanzhong region from 2011 to 2020 were analyzed.The nowcasting indicators of hail weather environment parameters and radar identification characteristics were summarized.The results showed that hail mainly occurred from May to August in the north of Guanzhong and mostly in June and July.Hailstorm had obvious diurnal variation characteristics,the main stage was 14:00 to 18:00.The warning indexes of unstable conditions for hail were K index≥25.0℃,temperature difference between 850 hPa and 500 hPa≥25.3℃,and Schaefer index≤-1.1℃.The warning index of energy condition was convective effective potential energy≥562 J/kg.The warning index of water vapor condition was temperature dew-point difference≥9.0℃.The early-warning index of vertical wind shear was deep wind vertical shear in 0-6 km≥7.3 m/s or shallow wind vertical shear in 0-3 km≥4.3 m/s.The height warning indexes of special layer were between 3.4-4.0 km for 0℃layer and 7.2-8.1 km for-20℃layer,respectively.The identification characteristics of dual-polarization radar were echo intensity equal to or more than 53 dBz,echo top height was more than 10 km,strong echo overhanging height was more than 1.8 km,and three-body scattering spike with length was more than 5.2 km.There was convergence in the lower layer of the velocity field,and the convergence intensity was more than 10.5 m/s.The maximum VIL was more than 15 kg/m^(2),the VIL increment was≥10 kg/m^(2),and the VIL density was≥2.6 g/m^(3).Polarization parameters such as differential reflectivity factor,differential propagation phase shift factor and zero delay correlation coefficient also had good indication significance for the recognition of hail.The forecast accuracy of the indicators was high,but there were certain empty predictions.
作者
刘帆
高萌
王瑾婷
刘军
乔丹杨
谢逸雯
LIU Fan;GAO Meng;WANG Jinting;LIU Jun;QIAO Danyang;XIE Yiwen(Meteorological Bureau of Xianyang City,Xianyang,Shaanxi 712000;Key Laboratory of Eco-environmental Meteorology for Qinling Mountains and Loess Plateau,Shaanxi Meteorological Bureau,Xi’an 710016;Binzhou Water Conservancy Bureau,Xianyang,Shaanxi 713500)
出处
《中国农学通报》
2023年第11期98-107,共10页
Chinese Agricultural Science Bulletin
基金
陕西省气象局秦岭和黄土高原生态环境气象重点实验室开放基金课题“基于双偏振雷达的强对流天气预警指示研究”(2020G-15)。
关键词
冰雹
探空资料
物理量
回波特征
预警指标
hail
sounding data
physical quantity
echo characteristics
nowcasting indicators