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    2022年7月环渤海地区一次中β尺度深对流云团强降水过程分析

    Analysis of a meso-β scale deep convective cloud cluster and heavy rainfall process in the Bohai Rim Region in July 2022

    • 摘要: 选用常规气象观测资料、FY-4A卫星资料和ERA5再分析数据,对2022年7月5—7日环渤海地区一次强降水过程的大尺度环境、动力条件,及中β尺度深对流云团的强迫作用、云团对强降水的反馈机制进行分析。结果表明:在高空槽和西太平洋副热带高压共同作用下,低空切变线和低空低涡为此次强降水过程对流云团的发展提供了有利动力条件。对流云团簇中有中β尺度深对流云团生成,并形成多个中尺度雨团,深对流云团的云顶亮温(TBB)低于-52℃,强降水过程一般发生在云团边缘的TBB梯度大值区。不稳定层结、水汽通量辐合、斜升气流相互作用,有利于深对流云团活动的发展增强。深对流云团内部及其附近区域的对流凝结潜热加热中心、非地转湿Q矢量散度的辐合中心与强降水中心位置较为一致,表明深对流云团通过对流凝结潜热加热,增强气流的上升运动强度,进而影响降水强度。

       

      Abstract: Based on conventional meteorological observation data,FY-4A satellite data and ERA5 reanalysis data,this study analyzes the large-scale environmental background,dynamical conditions,as well as the forcing mechanism of meso-β scale deep convective cloud clusters and their feedback mechanism associated with a heavy rainfall event over the Bohai Rim region during 5-7 July,2022.The results show that under the joint influence of an upper-level trough and Western Pacific subtropical high,low-level shear line and low-level vortex provided favorable dynamic conditions for the development of convective cloud clusters during this heavy rainfall process.Within the cloud cluster group,meso-β scale deep convective cloud clusters formed and developed into multiple mesoscale rain bands.The cloud-top brightness temperature (TBB) of these deep convective clouds was below -52 ℃,with heavy precipitation generally occurring in regions of large TBB gradients near the cloud cluster peripheries.The interaction of unstable stratification,water vapor flux convergence,and slantwise updrafts further enhanced the intensification and maintenance of deep convective cloud clusters.Moreover,the centers of convective condensation latent heating and the convergence zones of the divergent component of Q vector showed good correspondence with heavy rainfall centers,which indicating that convective condensation latent heat release within and around the deep convective cloud clusters strengthened the upward motion,thereby affecting rainfall intensity.deep convective cloud clusters enhanced updraft intensity through convective condensation latent heating,thereby affecting precipitation intensity.

       

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