尺度分离技术在一次切变线诱发西南涡暴雨个例中的应用

Application of Scale Separation Technology in a Case of Southwest Vortex Rainstorm Induced by a Shear Line

为探讨次天气尺度系统引发暴雨的主要机制和Shuman-shapiro滤波在盆地暴雨中尺度分离的效果,利用中国气象局逐小时降水加密观测资料、CMORPH融合格点降水资料、GFS全球预报场资料及FY-2E卫星相当黑体亮温(TBB)数据对2018年7月10-11日一次盆地暴雨过程(简称“7.11暴雨”)进行初步分析,结果发现,有利的大气环流形势下,冷空气人侵四川盆地后推动切变线南移并诱发西南涡是“7.11暴雨”产生的主要原因;Shuman-sha-piro滤波技术能够很好地分离出“7.11暴雨”中的次天气尺度扰动;热力性质不同的冷暖空气在四川盆地交绥,使大气斜压不稳定增强,对流层低层切变线及其伴随的西南涡为“7.11暴雨”的产生提供了有利的动力条件,同时配合有利的水汽条件,最终导致7.11暴雨的产生。

In order to explore the main mechanism of rainstorms caused by subsynoptic scale system and the effect of Shuman-shapiro filtering on scale-separation of rainstorm in basin,And based on the encrypted observation data of hourly precipitation,the CMORPH fusion grid precipitation data,the CFS global prediction field data and the FY-2E satellito equivalent blackbody brightness temperature(TBB)data in China Meteorological Administration,this paper made a se-ries of preliminary analysis upon the basin rainstorm process in July 10,2018 to July 11,2018(referred to as the“7.11 Rainstorm”),And it turms out that,under favorable atmospheric circulation conditions,the cold air invades the Sichuan Basin and pushes the shear line to the south and induces the southwest vortex(SWV)is the main reason for the"7.11 rainstorm".It further proves that Shuman-shapiro filtering technique can well separate the subsynoptic scale disturbances in“7.11 Rainstorm”.The cold and warm air with different thermal properties fought each other in Sichuan Basin which makes the phenomenon of atmospheric baroclinic unsteadily enhanced.The generation of lower tropospheric shear lines and its accompanying southwest vortexes have provided favorable dynamic conditions for the occurrence of“7.11 Rain-storm”,and at the same time,combined with favorable water vapor conditions,finally resulted in the occurence of 7.11 rainstorm.