高山雷达对低纬高原飑线的分析研究

 利用云南德宏新一代天气雷达飑线资料,同时结合另5次飑线个例,对比国内外一些研究成果,初步得出低纬高原飑线天气的一些中尺度指标.以德宏2006年7月17日飑线过程为例,分析了回波强度、回波速度场、气流的分布、地面风速等特点.结果表明:高低空急流是产生飑线灾害天气的重要因素;雷达强回波的中心强度、顶高等参数与天气过程存在较好的对应关系,可作为临近趋势预报的指标;按伯努里方程Δp/ρ=ΔV²/2可较好地估计地面风速,但需考虑地形影响和飑线方向的影响.结合雷达反演降水和德宏高密度雨量站资料,可看出飑线的强降水区域几乎都是其后部稳定的25～40dBz左右的稳定层状云回波造成的.

Analysis on squall line weather process in low latitude plateau by Mountaintop radar data

By using squall line data of new type weather Radar in Dehong,Yunnan,and contrasting with 5other squall line cases at the same time,some mesoscale indicators of squall line weather in low latitude plateau are obtained.By analyzing characteristics of echo intensity,echo velocity field,air stream distribution,surface wind velocity in squall line weather in2006-07-17 in Dehong,the results shows: upper and low-level jet stream is important factor causing squall line severe weather;parameters such as central intensity of strong Radar echo,height of top,etc.can be used as indicators of tendency now cast because of good correspondence with weather process.The velocity of surface wind can be better estimated according to Bernoulli's equation:Δp/ρ=ΔV²/2,but influences of topography and squall line direction should be considered.By combining with Radar precipitation retrieval and data of high density precipitation stations in Dehong,conclusions can be drawn that almost the whole heavy rain region is caused by stationary stratiform cloud echo about 25—40dBz in its rear part.