云南省文山州一次罕见的冬季暴雨过程分析

ANALYSIS OF A RARE WINTER RAINSTORM IN WENSHAN PREFECTURE,YUNNAN PROVINCE

利用常规气象资料、FNL 1°×1°再分析资料、雷达回波等资料,诊断分析2019年1月7~9日文山州罕见冬季暴雨天气过程的成因和特点,结果表明:(1)此次冬季暴雨过程是受南支槽加深东移、配合弱冷空气南下,冷暖空气交汇、促发不稳定能量的释放而产生。(2)具有持续时间长、累积雨量大、降水范围广等特点。(3)副热带高压的稳定维持,致使降雨时间较长。(4)700 hPa存在强烈的水汽辐合;低层辐合高层辐散的抽吸效应,强烈的垂直上升运动和大气层结不稳定,为此次强降雨的发生提供了有利的动力和热力条件。(5)过程期间,回波强度不强、稳定少动,有明显的风速辐合。

Based on the conventional meteorological data,FNL 1°x 1°reanalysis data and radar echo data,the causes and characteristics of the rare winter rainstorm weather process in Wenshan Prefecture from January 7 to 9,2019 are diagnosed and analyzed.The results show that:(1)the winter rainstorm process is caused by the deepening of the South Branch trough,moving eastward with weak cold air,the intersection of cold and warm air,and promoting the release of unstable energy.(2)It has the characteristics of long duration,large accumulated rainfall and wide range of precipitation.(3)The stable maintenance of subtropical high results in longer rainfall time.(4)There are strong water vapor convergence at 700 hPa,suction effect of low level convergence and high level divergence,strong vertical upward movement and instability of atmospheric stratification,which provide favorable dynamic and thermal conditions for the occurrence of heavy rainfall.(6)During the process,the echo intensity is not strong,stable and less moving,there is obvious convergence of wind speed.