偏东气流影响下保山市2次大到暴雨天气过程对比分析  

Comparative Analysis of Two Heavy to Torrential Rain Processes in Baoshan City under the Influence of Easterly Airflow

作　　者：祁倩 郭燕 QI Qian;GUO Yan(Baoshan Meteorological Office of Yunnan Province,Baoshan 678000,China)

机构地区：[1]云南省保山市气象局,云南保山678000

出　　处：《山地气象学报》2024年第5期11-19,共9页Journal of Mountain Meteorology

基　　金：云南省气象局基层台站气象科技创新与能力提升计划项目(STIAP202216):基于数值模式产品的秋季连阴雨预报。

摘　　要：【目的】对比分析保山市2021年和2022年2次大到暴雨天气过程的成因。【方法】利用常规观测资料、NCEP再分析资料和雷达资料,从环流背景、物理量、中小尺度系统演变特征等方面进行分析。【结果】2次过程均发生在热带低压西进,偏东气流影响的天气尺度背景下,低层辐合切变线动力抬升,配合良好的水汽,造成了保山市大范围的强降水天气过程;雨强的强弱时段与垂直螺旋度的变化相吻合,湿位涡对暴雨有较好的诊断效果。2次过程均为高质心回波,均表现出明显的低层辐合、高层辐散的特征,同时引导风较弱,强回波移速较慢,使得小时累积雨量较大。【结论】层积混合云降水回波反射率因子剖面明显的回波倾斜和强回波梯度区,径向速度剖面低层辐合、高层辐散的特征,可作为短时强降水的判别依据。Causes of two heavy to torrential rain weather processes in 2021 and 2022 in Baoshan City are comparatively analyzed based on the conventional observation data,NCEP reanalysis data and radar data from the perspective of circulation background,physical quantity,and the evolution characteristics of the meso-and small-scale systems.The results show that both of the heavy rain processes occurred when tropical depression moved westward and easterly airflows appeared.Low-level convergence shear lines were lifted dynamically,forming a wide range of heavy precipitation in Baoshan City accompanied by favorable water vapor conditions.The rainfall intensity was consistent with the variation of vertical helicity,and wet potential vorticity had a good diagnostic effect on heavy rainfall.Both of the heavy rainfall processes are reflected by high centroid echoes,featured by obvious characteristics of convergence at the bottom and divergence at the top.At the same time,the guiding wind was weak and the strong echoes moved slowly,which led to large amount of hourly accumulated rainfall.Thus,the characteristics of obvious echo tilt and strong echo gradient in the reflectance factor profile of the stratified mixed cloud precipitation echo,convergence at the bottom and divergence at the top of the radial velocity profile could be used as the basis of judging short-time severe precipitation.

关 键 词：暴雨 垂直螺旋度 湿位涡 雷达回波 

分 类 号：P458.121.1[天文地球—大气科学及气象学]