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2015 年6 月1 日江汉平原大暴雨过程诊断分析

The diagnostic analysis of heavy rainfall on 1 June, 2015 in Jianghan plain

  • 摘要: 应用常规观测资料、NCEP 1°×1°再分析资料及湖北省地基GPS 数据对2015 年6 月1 日江汉平原一次大暴雨过程进行诊断分析,结果表明:稳定强盛的水汽输送通道建立是大暴雨形成的基础,降水强度和范围则与水汽通量辐合中心和大气可降水量增量中心关系密切。强降水开始前对流层低层出现能量锋区,监利和洪湖地区位于暖平流控制下的高能舌中,气旋性环流显著。对流层低层正螺旋度的加强与气旋性暖式切变的增强相一致,高层强辐散、低层强辐合并配合正涡度,且整层均为强上升运动的形势为低层中尺度涡旋的新生和发展提供了有利的动力条件。在有利的环境条件下,暖切变线上发生发展的α中尺度低涡及地面暖低压倒槽中对应的β中尺度低压和涡旋最终导致了此次强降水过程。

     

    Abstract: Based on conventional metrological observation data, NCEP 1°×1° reanalysis data, and ground based GPS data in Hubei province,the heavy rainfall on 1 June, 2015 in Jianghan plain was analyzed. Results show that the strong and stable water vapor transportation channel is very important to the foundation of heavy rainfall. Intensity and range of heavy rain are closely related with convergence center of water vapor flux and incremental center of entire atmosphere precipitable water vapor. Before heavy rain occurrence, energy front in lower-level, warm advection, high θse , and remarkable cyclonic circulation appear in Jianli and Honghu. The strengthening of vertical helicity in lower-level is corresponding to the enhancing of cyclonic warm shear line. Strong divergence in upper-level, strong convergence and positive vorticity in lower-level, and strong upward motion throughout whole troposphere are favorable dynamical conditions of genesis and development of mesoscale vortex in lower-level. In favorable environmental conditions, the meso-α-scale vortex genesis and development in warm shear line, and the meso-β-scale low pressure and vortex in ground surface warm inverted trough result in the heavy rainfall process on 1 June, 2015 in Jianghan plain.

     

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