淮河下游初夏小时内降水分级与雷达信息特征  

Hourly precipitation classification and its radar information in the lower reaches of Huaihe River valley during early summer

作　　者：王坚红[1] 孙素琴[1] 苗春生[1] 王群 徐良谋 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]盐城市气象局,江苏盐城224001

出　　处：《气象与环境学报》2010年第2期1-6,共6页Journal of Meteorology and Environment

基　　金：国家自然科学基金项目(40776017);淮河流域气象开放基金(20080170);国家908海洋综合调查子课题(2654)项目;国家908扩展项目(908-01-BC21);南京信息工程大学校级课题(QD45)共同资助

摘　　要：利用淮河下游盐城市多普勒天气雷达和雷达扫描范围内建湖县降水量资料,对2008年6月的6次小时内三等级降水过程进行环流背景和局地雷达信息特征分析,其中对不同等级降水又给出夜雨及午后雨降水日变化分类。在环流背景基础上,通过综合分析对应各级各类降水的多普勒天气雷达降水回波的滤波强度分布特征,以及相应时空的雷达径向风场沿体扫倾斜面的分布结构,归纳出小时内降水量级的动力信息特征。结果表明:在两类主导性天气尺度环流背景下,局地雷达要素空间分布特征为:同等量级降水,夜间的平均回波强度明显弱于白天;上游补充回波范围指示降水连续性质;上游长而强的回波带维持下一小时短时强降水;沿经建湖的局地雷达倾斜体扫半径剖面,径向风的风向风速辐合中心的高度越低,辐合层次越宽厚,对应的降水级别越大;在同等降雨量级中,沿倾斜的体扫半径的局地风速强切变,通过上下动量传递和水汽混合,维持着更强的降水。Based on Doppler weather radar data from Yancheng radar station and precipitation data from Jianhu weather station in the lower reaches of Huaihe River valley,the general circulation background and local radar information on six hourly-rainfall events in June 2008 were analyzed.Six hourly-rainfall events were classified into three grades,and were further divided into two types,i.e.night rain and afternoon rain.Local temporal-spatial distributions of filtered radar echoes and the corresponding radial wind structures at the slanted scanning surfaces,the dynamic information characteristics of hourly precipitation classification were summarized according to the general circulation background.The results indicate that the mean echo intensity is weaker in night than in daytime for the same precipitation classification under two dominant types of synoptic circulations.The precipitation continuity is influenced by the upstream echo.The longer and stronger upstream echo band will support the heavy rainfall within next hour.Along the slanted scanning semi-diameter over Jianhu,the lower convergence center of radar radial wind speed and direction is,the deeper convergence layer is,and the larger the corresponding precipitation grade is.The strong shearing of the local radial wind along the slanted scanning semi-diameter will support the heavy rainfall by momentum and vapor transference between layers for the same precipitation classification.

关 键 词：初夏小时内降水分级 环流背景类型 雷达降雨回波 局地体扫倾斜面 径向风风速风向 淮河下游 

分 类 号：P426.6[天文地球—大气科学及气象学]