临沂地区一次冰雹过程的中尺度特征分析

Analysis on the Meso-scale Characteristics of a Hail Process in Linyi Area

[目的]研究临沂地区一次冰雹过程的中尺度特征。[方法]综合利用MICAPS常规观测数据、地面加密自动站、MM5模式产品及多普勒天气雷达资料等观测资料,分析了2010年5月30日发生在山东半岛及鲁东南地区的一次强对流冰雹天气过程,探讨此次强对流天气发生的环流背景、物理机制以及中小尺度系统特征,并从中找出一些这类天气发生、发展的规律。[结果]此次强对流天气主要是受冷涡横槽的影响;高空西北气流、低空西南气流以及高空干冷、低层暖湿,加上前倾槽的配置,从而产生强对流天气。雷达回波分析表明,此次过程雷达回波属于典型的多单体风暴回波,强回波区位于回波最前沿,对流发展最剧烈时回波强度达65 dBz,回波顶高超过11km,且伴随风暴单体的发展,不断有垂直液态水含量产品大值区跳跃性生消,并存在明显的弱回波区;风暴单体随着降水系统向东南方向移动,在单体移动方向的右前侧表现出钩状回波特征。分析冰雹天气发生前后不同仰角上径向速度场的演变特征发现,径向速度场在冰雹天气发生前有一些预兆性的变化。用多普勒雷达产品改进MM5模式的初始场,可以一定程度上改善预报效果,提高短时、临近预报的准确度。[结论]该研究为今后强对流天气的短时、临近预报工作积累了经验。

[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area.[Method] By comprehensively using MICAPS conventional observation data,ground encryption automatic station,MM5 model product and Doppler weather radar data,a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30,2010 was analyzed.The circulation background and physical mechanism of strong convection weather occurrence,the features of meso-and micro-scale systems were discussed.Some occurrence and development rules of such weather were found.[Result] The strong convective weather was mainly affected by the cold vortex and translot.The high-altitude northwest airflow,low-level southwest airflow,dry and cold air in the high layer,warm and wet air in the low layer,forward-tilting trough caused the strong convective weather.The radar echo analysis showed that the process belonged to the typical multi-monomer windstorm echo,and the strong echo zone was in the forefront of echo.When the convection development was the strongest,the echo intensity reached 65 dBz,and the echo top height surpassed 11 km.As the development of windstorm monomer,the big value zone of vertical liquid water content product had the jumping formation and disappearance.Moreover,the obvious weak echo zone existed.The windstorm monomer moved to the southeast direction as the precipitation system.In the right front of monomer moving direction,there was hook echo feature.The evolution characteristics of radial speed field at the different elevation angles before and after the hail weather occurrence were analyzed.It was found that the radial speed field had some premonitory variations before the hail weather occurrence.Doppler radar product was used to improve the initial field of MM5 model,which could improve the forecast effect in the certain degree and the accuracy of short-time forecast and nowcasting.[Conclusion] The research accumulated the experience for the short-term forecast and nowcasting work of strong convective weather in future.