2001—2010年大连地区暴雪天气与雷达回波特征分析

利用2001—2010年大连市7个市区县观测站冬季降水资料、常规观测资料和大连新一代天气雷达（CINRAD/SC型）回波资料,对发生在此期间8次暴雪过程环流形势分析的基础上,对雷达回波特征进行分析。结果表明：造成大连地区暴雪天气的环流形势,在500 hPa高空上多与东亚大槽建立前自中国华北伸向黄淮地区的高空槽有关,在地面上则与经华北南部和江（黄）淮地区东移或北上气旋（倒槽）与北方南下冷高压在大连附近交绥有关。雷达回波速度场以＂暖式切变＂型最多;该类型的降水强度,随南北气流的增强、风切变的增大和切变层在边界层和对流层低层的抬升与暖平流的匹配而加强;随西南气流在边界层和对流层低层减弱与冷平流的出现而减弱。研究结果可为预报冬季暴雪天气提供参考。

An analysis of snowstorm and radar echo characteristics from 2001 to 2010 in Dalian

Based on the winter precipitation data at 7 weather stations,the conventionally observational data and the new generation weather radar（CINRAD/SC）data in Dalian from 2001 to 2010,the circulation situations of 8 snowstorm cases occurred during this period and their radar echoes characteristics were analyzed.The results indicate that the synoptic situation causing snowstorm is related to upper trough formed over north China and stretching towards Huanghuai area before the formation of East Asia trough in 500 hPa.Accordingly,it is related to the eastward or north cyclone（inverted trough）from the south of north China and Jianghuai（Huanghuai）areas and the encounter with southward cold high in Dalian on surface level.The ＂warm-shear＂ type is the most in radial velocity field of radar echo and its precipitation intensity increases with the increasing of south and north branches airflows and wind shear,the lifting of shear layer at boundary layer and lower troposphere as well as the occurrence of warm advection,while it decreases with the weakening of southwest airflow at boundary layer and lower troposphere,and the occurrence of cold advection.This study could provide references for snowstorm forecast.