东北南部强降雪天气的多普勒雷达产品特征

本文利用营口、沈阳新一代多普勒雷达产品,分析了2004年-2007年3次东北南部强降雪天气过程。研究发现东北南部强降雪天气在基本反射率产品上18dBZ以上回波面积一般大于5000km2,1h降雪量与降雪回波呈正相关。雨雪交界处回波强度有较大梯度。强降雪回波强度一般在30dBZ以下,回波强度在40dBZ以上时,以液态降水粒子或处于融化状态的固态降水粒子为主。根据雷达回波强度及梯度,结合探空和地面温度可以判断降水性质和雨雪分界,具有一定预报意义。强降雪过程开始阶段零速度线较清晰,呈"S"型,为暖平流风场结构;发展成熟阶段暖平流与大尺度辐合风场叠加形成复合风场结构,预示降水回波将达到最强。风廓线产品中低空水汽输送对降水强度的变化有很直观的指示意义。强降雪过程中回波顶高度低,起伏不大,比较平整,面积略小于回波强度产品面积;垂直液态水含量产品对于降雪明显低估,其面积比回波面积小得多。

Features of Doppler Radar Products of Heavy Snow in the Southern Northeast China

Hazards of heavy snow have become increasingly serious in recent years in the context global warming, which would result in great loss and damages of natural and social systems. Demands for analysis and warning methods for heavy snow are therefore increasing. There have been a series of studies on the features of Doppler radar products in heavy snow processes in some other countries but little work has been done in China so far. Therefore, there is an urgent need to investigate the features of Doppler radar...