The Analysis of Radar Echo Features of a Local Torrential Rain in Tongren

In order to explore the occurrence reason and development prdess of torrential rain,so as to decrease the loss brought by local torrential rain in agricultural production and increase the forecast accuracy of torrential rain,the authors used a new Doppler weather radar data,and combined with conventional meteorological data and rainfall observation records to analyze a local rainstorm weather process on September 10,2013in the middle part of Tongren,Guizhou.Results:1)The direct reason for the heavy rain weather in some areas of Tongren was low trough,low vortex deepening,low vortex shear line and the West Pacific subtropical high and stable less dynamic barrier eastward and ground cold air intrusion.2)In the mixture of rain clouds,scattered laminated hybrid echo kept stable,less dynamic, gathered aquasistationary stateand strong echo rainband constitute thetrain effectsin a long time was conducive to the heavy rainstorm weather.3)In the mixed precipitation echoes in the presence of multiple convective echo column,strong echo nucleus located in the lower cloud was important to recognize and judge the feature of rainstorm.In the radial velocity,The change of positive and negative velocity and zero velocity line could reflect the development process of the rainstorm weather.4)Before the occurrence of the rainstorm,the intensity and the thickness of convergence of troposphere was enhanced,and divergence emergenced;in the weakening stage,low level convergence weaken and gradually became divergence, divergence was also gradually weakened,and finally into the sinking in the whole.In the radial velocity figure,the variation of plus or minus speed zone and zero velocity curve reflected the evolution process of torrential rain.