浙东海岛两次强对流天气对比分析

对比分析了2004年发生在舟山的两次相似的强对流天气过程,不同在于一次过程强降水特别突出,一次过程强风特别突出。通过对两次过程反射率因子、径向速度以及一些二次产品的对比分析,找出了一些相同点和不同点。组织结构性好的强回波、速度产品中的大风区、垂直风切变、较高的顶高和大的VIL值等是产生雷雨大风和短时强降水天气的共同特征。回波移速较慢的易产生强降水,回波移速快的易产生强风。强风天气的回波强度、顶高和VIL等产品都有更强的表现。低层水平风的辐合、中气旋、垂直风向切变等可以产生强降水,中高层的中气旋、垂直风切变可以产生下击暴流、冰雹等强对流天气。

Contrastive Analysis of Two Severe Convective Weather Cases over Coastal Zhejiang Islands

A comparative analysis is made of two severe convective weather events occurred over the Zhoushan islands in 2004 by means of the data from new generation Doppler weather radar.One has extreme rainfall,while the other has extreme gales.The reflectivity,radial velocity and other secondary radar products of the two cases are analyzed,and some similarities and differences are found out.Both cases have seen organized strong echoes,strong wind areas in radial velocity pictures,vertical wind shear,high echo tops,and large VIL(Vertical Integrated Liquid water).Heavy rainfall happened when the echoes moved slowly while strong gales happened when the echoes moved quickly.The case of extreme gales had higher echo top,greater reflectivity and VIL.The wind convergence,mesoscale cyclone and vertical wind shear at lower levels may produce heavy rainfall.The mesoscale cyclone and vertical wind shear at middle and upper levels may produce strong downburst or hails.