应用全型散度方程诊断鄂东北一次梅雨强降雨  

Diagnostic Analysis of a Meiyu Heavy Rain in Northeast Hubei Province by Using Divergence Equation

作　　者：张端禹[1] 许建玉[1] 赵玉春 Zhang Duanyu Xu Jianyu Zhao Yuchun(Hubei Key Laboratory for Heavy Rain Monitoring and Warning Reserch, Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205 Xiamen Meteorological Service, Fujian, Xiamen 361012)

机构地区：[1]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,武汉430205 [2]福建省厦门市气象局,厦门361012

出　　处：《气象科技》2016年第6期1009-1015,1029,共8页Meteorological Science and Technology

基　　金：国家自然科学基金(41375057;41328007;41105073);暴雨监测预警湖北省重点实验室暴雨研究开放基金(IHR201401);我国暴雨灾害信息情报(IHRKYYW201605)共同资助

摘　　要：利用0.5°×0.5°GFS分析资料和常规气象观测资料,分析2013年7月5—7日鄂东北梅雨连续暴雨过程。结果表明:1降雨具有比较明显的日变化,夜间加强,白天减弱;鄂东北低层辐合也有与降雨强度一致的日变化特点。2散度变率在高层出现正值、中低层出现负值有利于降雨加强,且这种变化比暴雨发生稍有提前。一般傍晚散度变率在低层即出现负值,这有利于夜间低层辐合加强。3利用全型散度方程2项组合诊断发现,虽然非线性平衡方程偏差项确是散度变率的主要项,但在降雨开始阶段只有余项在低层出现较为明显的负值。4利用全型散度方程4项组合诊断发现,边界层水平风场辐合是降雨启动因子之一;非地转平衡项在近地面出现较大正值对于降雨减弱有较好的指示;与垂直运动有关的项在降雨峰值阶段中层负值较大。By using the 0.5°×0.5°GFS and conventional observational data,a Meiyu heavy rain took place from 5to 7in July 2013 over the northeastern Hubei Province is analyzed.The results show：（1）The rainfall has obvious diurnal variations：increased at night and decreased in the day time;the convergence at low levels had the same tendency with that of the rainfall.（2）Positive divergence variability at upper levels and negative divergence variability at middle and low levels were favorable to rainfall increase.These changes were ahead of the heavy rainfall.Negative divergence variability at low levels began in the evening,which was helpful to the convergence increase at low levels at night.（3）By the divergence equation with two-item combination,it is found that although the deviation of the nonlinear balance equation is the main item of divergence variability,the remainder is the only item whose value became obviously negative in the beginning stage of the heavy rain.（4）By the divergence equation with four-item combination,it is found that the convergence in the boundary layer was one of the rain trigger factor;the ageostrophic equilibrium item with large positive value in the near surface indicated the weakening of the rain well;and item in connection with upward motion had large negative values at the middle levels in the peak rain stage.

关 键 词：梅雨暴雨 散度 散度变率 全型散度方程 

分 类 号：P444[天文地球—大气科学及气象学]