云南一次短时强降水过程的中尺度特征及成因分析

Analysis on Meso-scale Features and Forming Reasons of a Short Time Intensive Precipitation Case in Yunnan Province

为揭示云南短时强降水的成因,提高短时强降水的预报准确率,应用常规观测资料、卫星、多普勒雷达和闪电定位资料对2013年6月9-10日发生在云南一次较大范围的短时强降水过程的中尺度特征及成因进行分析,研究表明:冷锋切变线提供动力抬升条件触发不稳定能量释放,诱发短时强降水;高空槽后冷平流的补充南下激发云南金沙江河谷地区中尺度对流系统(MCS)不断生成并南移,使得MCS维持较长时间,为滇中及滇南短时强降水的发生提供有利条件,短时强降水出现在MCS和中尺度对流单体(MCC)云团移向的前部边缘地区;雷达回波资料显示,飑线的维持和移动造成滇南的短时强降水,短时强降水发生在飑线前部的入流槽口处,云南中部的短时强降水与逆风区的形成和维持有直接关系;负地闪频数最大值出现的时间比短时强降水的发生有30 min^3 h左右的提前量,负地闪频数的跃增对短时强降水的预测预警有较好的指示作用。

In order to reveal the forming reason of short time intensive precipitation in Yunnan province and increase forecasting accuracy rate of intensive precipitation,conventional observation data,satellite data,doppler radar echo and lightening locating data were used to analyze the forming reason and meso-scale features of a wider range short time intensive precipitation case in Yunnan province from June 9 th to June 10 th in 2013. Research indicated that cold front shear line triggered the releasing of unstable energy,which induced the short time intensive precipitation. It moved southward of cold advection in back of the high-level and made the MCS in Jinshajiang Valley of Yunnan grow,and then the MCS moved southward. For this reason,the MCS maintained a longer lifetime,then it caused the short time intensive precipitation in middle and in south of Yunnan,and short time intensive precipitation happened at foreside brink of MCS and MCC cloud＇s moving direction. Radar echo indicated that the maintaining and moving of squall line made the short time intensive precipitation in south Yunnan which happened at inflow nick in front of quall line,and the forming and maintaining of adverse wind regions contributed directly to the short time intensive precipitation in middle of Yunnan.The appearing time of CG lightning frequency number＇s maximum value was 30 min-3 h earlier than short time precipitation. So CG lightning frequency number＇s increase vast scaly can denote the forecasting or warning for short time precipitation.