华北平原两次大气波导CINRAD/SA超折射回波分析

Comparative Analysis on the Atmospheric Duct and CINRAD/SA Super-Refraction Echoes of Two Cases in North China Plain

利用CINRAD/SA雷达资料结合探空实况对2007年7月8日和8月23日发生在华北平原的两次不同类型的大气波导进行了分析。结果表明:大气波导与大气温度、湿度等气象要素的垂直分布密切相关,不同类型大气波导的气象要素垂直分布存在差异,并在CINRAD/SA雷达产生不同类型的超折射回波,当雷达站存在表面波导时,形成了2层模式超折射回波;当雷达站存在抬升波导时,形成了3层模式超折射回波。超折射回波能够反映低层大气的垂直结构变化,2层模式超折射回波预示着雷达站附近大气层结稳定;3层模式超折射回波表示雷达站附近存在低层湿冷、上层干热的大气垂直结构。超折射回波主要分布在太行山东部平原地区,超折射回波目标的可视位置与实际位置存在偏差,特别是高度偏差较大。不同类型的超折射回波对未来天气具有一定的指示意义,可为雷达回波空间定位及强对流天气的监测、预报提供科学依据。

The two different kinds of atmosphere duct in North China Plain on 8 July and 23 August,2007 are comparative studied using the CINRAD/SA radar combining sounding data.The results-indicate that the atmospheric duct has correlation with the vertical change of meteorological factor such as temperature,humidity,and so on.There are some differences in vertical distribution of meteorological condition among different kinds of atmospheric duct.Different kinds of atmospheric duct-form different super-refraction echoes also.If there is surface atmosphere-duct at radar site,it forms 2 layer mode super-refraction echoes.If there is lifting atmospheric-duct at radar site,it forms 3 layer mode super-refraction echoes.Super-refraction echoes reflect the change of vertical configuration-of atmosphere.The 2 layer mode super-refraction echoes indicate the atmosphere near the radar site is stable.The 3 layer mode super refraction echoes indicate that the vertical distribution of atmosphere is humid and cold air on lower layer and dry and hot air on upper layer at the radar site.There are mainly super-refraction-radar echoes in the plain in the east of Taihang Mountain.The super-refraction radar echoes bring more measuring error,expressly in the height.These provide the science basis for the spatial location of echoes,the monitor and forecast of severe convection weather-in North China Plain-by Doppler radar.