2015年肇庆开汛暴雨环境条件和雷达风廓线产品特征分析  

Analysis of the Environmental Conditions of the First Heavy Rain of Raining Season of 2015 in Zhaoqing and the Characteristics of Wind Profilers Products

作　　者：翁佳烽 周义昌 郭春辉 李文辉 WENG Jia-feng ZHOU Yi-chang GUO Chun-hui LI Wen-hui(Meteorological Bureau of Zhaoqing City, Zhaoqing 52604)

机构地区：[1]肇庆市气象局,广东肇庆526040

出　　处：《广东气象》2017年第4期37-40,48,共5页Guangdong Meteorology

摘　　要：利用常规观测资料、Micaps资料、NCEP 1°×1°再分析资料和雷达风廓线资料,对2015年肇庆市开汛暴雨过程的环境条件及雷达风廓线产品特征进行分析。结果表明:暴雨发生在200 h Pa高空气流分流区、700 h Pa显著西南气流前方、850 h Pa切变线以南风速辐合区、925 h Pa风场辐合区和地面锋面低槽的重叠区域。暴雨发生前伴随着CAPE值激增,在大气层结极不稳定条件下,西南暖湿气流北上在广东中部地区辐合汇聚,为暴雨提供大量水汽和不稳定能量。暴雨过程低层气旋式涡度和高层反气旋式涡度使得低层辐合和高层辐散更加深厚,进一步增强上升运动。暴雨期间雷达风廓线资料直观地显示了中小尺度系统引起的风场变化,中层波动对应过程中的几个强降水时段。当上空处于中层西风波动槽前时,西南暖湿气流层次深厚,降水加强;当6 km以上高度西北气流向下发展时,降水处于减弱阶段。Using conventional observations, Micaps data, NCEP reanalysis and wind profilers data, we studied the environmental conditions of the first heavy rain of raining season of 2015 in Zhaoqing and the characteristics of wind profilers products. The result is shown as follows. This heavy rain took place in an area that saw the diversion of an upper-level flow, the front of a significant southwesterly flow at 700 hPa, the convergence of wind velocity south of a shear at 850 hPa and the superimposition of a converged 925-hPa wind field and a frontal trough at the surface. Prior to the heavy rain, the CAPE value increased dramatically, and under the atmospheric conditions of extremely unstable stratification, the southwesterly flow moved northward to converge in central Guangdong, providing large amount of water vapor and instability energy. During the rain, low-level cyclonic vorticity and upper-level anti-cyclonic vorticity deepened the low-level convergence and upper-level divergence, further strengthening the ascending motion. The wind profiler gave visual display of the changes in the wind field caused by meso- and fine-scale systems and a few periods of intense rain corresponding to mid-level waves. The rain was intensified as a mid-level westerly trough came close and a warm and humid layer of southwesterly thickened. When northwesterly flows above the altitude of 6 km developed downward, the rain was weakened.

关 键 词：天气学 暴雨 切变线 雷达风廓线 肇庆市 

分 类 号：P44[天文地球—大气科学及气象学]