摘要
利用山西4部C波段多普勒天气雷达基数据和地面观测资料,对2009-2017年山西出现的38次多普勒雷达V型缺口特征进行统计分析,研究多普勒雷达V型缺口特征与降雹的对应关系,总结V型缺口对冰雹的预报预警指标,并在2018-2022年开展实时业务应用,对V型缺口特征及预报预警指标进行检验并订正。结果表明:降雹在V型缺口出现后开始,在V型缺口消失前结束;降雹概率与V型缺口起始高度无明显的对应关系;V型缺口对应的上升气流高度≤4 km时无降雹;V型缺口理想的观测仰角为2.4°~6.0°,最佳观测仰角为2.4°;强回波区呈现“蝴蝶状”是降雹最强阶段。降雹开始阶段预报预警指标及关注点:(1)V型缺口有弱回波区或有界弱回波区;(2)初始V型缺口沿径向长度>30 km,当≤30 km时上升气流伸展高度要超过4 km;(3)平均径向速度具有低层辐合高层辐散特征。满足以上3点可预报有冰雹出现,如果V型缺口首先在6.0°仰角观测到,可预报有大冰雹出现(直径大于1 cm),并立即发布预报预警信号。冰雹持续期间预报预警指标及关注点:(1)>50 dBZ强回波中心连续下降且回波顶高>10 km;(2)V型缺口对应的弱回波区呈倾斜状;(3)弱回波区或有界弱回波区稳定维持;(4)当在0.5°仰角观测到V型缺口时可预报冰雹仍在持续;当强回波区呈现“蝴蝶状”,可预报降雹强度增强;(5)当V型缺口最大垂直液态水含量>22 kg·m^(-2)、垂直液态水含量跃增量>26 kg·m^(-2)、垂直液态水含量密度>3.6 g·m^(-3)时,出现冰雹的概率较大。
Using the basic data from four C-band Doppler weather radars and ground observation data in Shanxi province,the statistical analysis of the V-shaped gap features observed in Shanxi from 2009 to 2017 was conducted.The correspondence between V-shaped gap observed by Doppler radar and hailfall was investigated,and the forecasting and warning indicators for hail using V-shaped gap features were summarized.Real-time operational applications were carried out from 2018 to 2022 to validate and refine forecasting and warning indicators of the V-shaped gap.The results indicate that hailfall begins after the appearance of V-shaped gap and ends before their disappearance.There is no significant correlation between the probability of hailfall and the initial height of V-shaped gap.When the corresponding updraft height of V-shaped gap is≤4 km,hailfall does not occur.The ideal observation elevation angle for V-shaped gap ranges from 2.4°to 6.0°,with 2.4°being the optimal angle.The strongest phase of hailfall is characterized by a"butterfly-shaped"intense echo region.The predictive indicators and focal points during the initial stage of hail forecasting and early warning include:(1)the presence of a weak or marginally weak echo region when a V-shaped gap appears;(2)a length of the V-shaped gap along the radial direction>30 km,or an initial length of the V-shaped gap along the radial direction<30 km and an updraft extending above 4 km;(3)average radial velocity showing low-level convergence and high-level divergence characteristics.Meeting these three criteria can predict the occurrence of hail.If a V-shaped gap is first observed at a 6.0°angle,a forecast can be made for the occurrence of large hailstones(with a diameter greater than 1 cm),and an immediate forecasting and warning signal can be issued.The predictive indicators and focal points during the duration of hail include:(1)continuous decrease in the height of the strong echo center>50 dBZ and echo top>10 km;(2)a slanted weak echo region corresponding to the V-shaped
作者
李腊平
杨淑华
刘洁莉
赵琦
李小强
王嘉媛
LI Laping;YANG Shuhua;LIU Jieli;ZHAO Qi;LI Xiaoqiang;WANG Jiayuan(Datong Meteorological Bureau of Shanxi Province,Datong 037010,Shanxi,China)
出处
《高原气象》
CSCD
北大核心
2024年第3期749-761,共13页
Plateau Meteorology
基金
中国气象局2018年预报员专项(CMAYBY2018-012)
大同市气象局创新团队项目(2023-01)。
