一次前倾槽下混合强对流天气关键信息分析

Mixed Strong Convective Weather Under a Forward Trough: Key Information Analysis

为加强防灾减灾能力,克服强对流过程预报失误问题,本研究综合利用多源气象观测资料,对2018.6.29浙江省中南部一次混合强对流过程进行分析。结果表明:前倾槽、地面辐合线及地形抬升,导致新生对流的发展、维持;前期不稳定能量累积明显,高Cape、θse能量大值区和925 hPa比湿都对此次强对流强度有较好的指示意义,但逆温层及干侵入导致K指数参考意义差;降雹风暴中气旋出现了9个体扫并伴有强风切变,同时VIL跃增相对降雹时刻有18 min提前量,为短临预报争取了预警时间;本次过程ρVIL表现出高敏感性,将估测冰雹直径≥5和ρVIL≥4结合会对冰雹有更好的指示意义;VIL指数结合VILmax和ρVILmax可推断出风暴性质;风暴承载层抵消作用导致此次雹云风暴移动发展受限。

To strengthen the capacity of disaster prevention and mitigation,overcome the prediction errors of strong convection process,we analyzed a mixed strong convective event in south-central Zhejiang on June 29,2018 based on multi-source meteorological observation data.The results showed that:the forward trough,surface convergence line and orographic uplift led to the development and maintenance of new convection;the accumulation of unstable energy in the early stage was obvious;high Cape,θseenergy cumulation zone and925 hPa specific humidity had good indicative significance for this strong convection intensity;but the inversion layer and dry intrusion led to poor reference of K;9 body sweeps and strong wind shear occurred in the mesocyclone during hailstorm;at the same time,the jump of VIL was 18 min ahead of the hail time,providing early warning time for short-term forecast;high sensitivity ofρVILwas showed in this process,and combining the estimation of hail diameter(≥5)and VIL(≥4)could provide the better significance;the combination of VIL with VILmaxandρVILmaxcould deduce the property of the storm;the offsetting effect of storm bearing layer resulted in the limited development of the hailstorm.