雨雪冰冻天气多普勒雷达产品特征

Characteristic Analysis of Snowy and Freezing Weather with Doppler-Radar Data

2008年1月下旬至2月上旬福建省西部北部出现了历史罕见的雨雪冰冻灾害。利用多普勒雷达反射率、回波顶高、径向速度、垂直风廓线等产品对此次雨雪冰冻天气进行特征分析,通过分析发现:①冰晶和雪的回波强度通常比连续性降水回波弱,在反射率图上,回波表现为边缘毛松,丝缕状纹理结构明显,边缘模糊不清,没有确定的边界;②回波顶高和零度层较低,因为垂直方向大气相对较稳定,不利于对流发展,降水粒子没有发展到高空;③在径向速度图上存在牛眼,说明在低空有急流存在。在低层有环形的零速度线,中高层的零速度线为倒"S"形,表明低层有风切变存在,中高层有冷平流;④风廓线图上高层为西南风,中层为西北风,低层为西南风,近地层为东北风。说明从近地层到高层为"冷-暖-冷-暖"的层结结构,有利于冻雨天气形成。

From late January to early February in 2008,there occurred rare snowy and freezing weather in the northwestern Fujian.The characteristics of the snowy and freezing weather are analyzed in terms of reflectivity,echo top,radial velocity,and VWP products from Doppler radar.The results indicate:(1) The echo intensity of ice and snow is weaker than that of continuous precipitation.(2) The heights of the echo top and zero layer are relatively low.(3) There exists a structure with a shape of a cow s eye on the rad...