山东一次强对流天气的环境条件和对流风暴特征

Environmental Conditions and Convective Storm Features of a Severe Convective Weather Process in Shandong Province

利用常规观测资料、地面加密自动站资料、多普勒天气雷达资料以及NCEP/NCAR再分析资料,对2016年6月14日山东一次强对流天气的环境条件、风暴特征进行了分析。结果表明:(1)6月14日强对流天气主要发生在横槽转竖引导冷空气南下和低层暖湿气流交汇的环流形势下,地面辐合线是抬升机制。上干下湿的不稳定层结、低层水汽充沛及湿层厚是出现短时强降水的重要原因。假相当位温差(△θse)和风暴相对螺旋度(SRH)对强对流天气有较好的指示意义;(2)较低的融化层高度、适宜的0℃层和-20℃层高度是大冰雹的发生指标。抬升凝结高度低、P_(WV)较大等对短时强降水具有指示作用;(3)垂直风切变较大,风暴承载层平均风远大于风暴移动速度,致使超级单体持续时间长,并具有高悬强回波、有界弱回波区、回波悬垂、风暴顶辐散、倒"V"型缺口、中层径向辐合、中气旋、"钩"状回波和三体散射等回波特征;(4)降雹发生在Z_(max)大值期、VIL和DVIL最大时段、HGT增高期。中气旋厚度、最大切变和持续时间与天气的强烈程度密切相关。

Based on the conventional observation data,ground-encryption automatic station data,Doppler weather radar data and NCEP/NCAR reanalysis data,the environmental conditions and storm characteristics of a severe convective weather were analyzed in Shandong Province on 14 June 2016. The results are as follows：（ 1） The strong convective weather mainly occurred under the circulation situation of the transversal trough changing to be vertical and guiding the cold air southward and meeting the low-level warm moist air flow,and the ground convergence line was the uplift mechanism. Wet unstable stratification,low level plentiful water vapor and wet layer thickness were the important reasons for short-term heavy precipitation. The value of △θ_（se（ 500-850））and SRH had a good indication to the srong convective weather.（ 2） Lower melting level,suitable heights of 0 ℃ and-20 ℃ were important to large hailstorm.The lower height of uplift condensation and the larger P_（WV） were indicative to heavy rainfall.（ 3） The vertical wind shear was larger and the average wind speed of storm bearing layer was greater than the moving speed of storm,which led to long duration of supercell. It had radar echo characteristics such as hanging strong echo,bounded weak echo region,echo pendency,storm top divergence,inverted＂V＂type gap,middle radial convergence,mesocyclone,hook echo and three-body scattering.（ 4） The hail process occurred in the period of maximum value of Z_（max）,VIL,D_（VIL）,and the increase of HGT. The thickness,maximum shear and duration of the middle cyclone were closely related to the intensity of the weather.