2015年8月3日豫北一次区域暴雨成因分析

Analysis on the Cause of Regional Heavy Rain in North Henan Province on August 3,2015

利用Micaps常规观测资料、NECP再分析资料和数值预报产品,采用天气学诊断分析方法对2015年8月3—4日河南省北部一次区域暴雨过程的形成机制进行分析。结果表明:该次暴雨过程是发生在深厚的蒙古低涡低槽前的上升运动区和700 h Pa切变线附近;副热带高压西侧西南急流为降水区提供了充足的水汽;地面辐合线为局地出现强对流天气提供了有利的辐合抬升和触发条件。垂直速度及其散度场等物理量对暴雨的发生有很好的指示意义,其演变可为暴雨的发生、发展以及落区、降水时段预报提供有力的预报依据。较大的降水出现在云团爆发性发展与合并时。"列车效应"导致豫北区域暴雨甚至大暴雨天气产生;逆风区的出现和冷平流的维持使得暴雨中出现短时强降水;细网格数值预报产品降水预报资料在该次降水预报中有较好的指示作用,对降水落区的把握有一定偏差。

Based on the conventional observation data of Micaps,NECP reanalysis data and numerical forecasting products,the formation mechanism of a regional heavy rain process in northern Henan province from August 3 to 4,2015 was analyzed by means of weather diagnostic analysis.The results showed that the process of the heavy rain was occurred in the ascending motion area and the 700 h Pa shear line before the deep Mongolia vortex and trough; the southwest jet of the west side of the subtropical high provided abundant water vapor for the precipitation area; the surface convergence line provided favorable convergence rise and triggering conditions for the local strong convective weather.The physical quantities of vertical velocity,its divergence field and so on were very instructive for the occurrence of heavy rain.The evolution could provide a strong forecast basis for the occurrence,development and target area and precipitation period forecast of the heavy rain.The larger precipitation occurred when the cloud was explosive development and merger.The "train effect" caused the rainstorm and even the heavy rainstorm in the northern Henan region.The emergence of the upwind area and the maintenance of the cold advection caused the short-term heavy rainfall in the heavy rain.The precipitation forecast data of refined net numerical forecast products had better indication function in the precipitation forecast,and the grasp of the precipitation area had a certain deviation.