甘肃河东地区不同环流形势下短时强降水的雷达回波特征分析  

Analysis of Radar Echo Characteristics of Short-term Heavy Precipitation Weather with Different Circulation Pattern in East Gansu Province

作　　者：孔祥伟 杨建才[2] 李红[3] 杨毅 KONG Xiangwei;YANG Jiancai;LI Hong;YANG Yi(College of Atmospheric Sciences,Lanzhou University/Joint Center of Research and Training for Weather and Climate Prediction,Lanzhou 730000,Gansu,China;Lanzhou Central Meteorological observatory,Lanzhou 730020,Gansu,China;Institute of Arid Meteorology,China Meteorology Administration,Lanzhou 730020,Gansu,China)

机构地区：[1]兰州大学大气科学学院/兰州天气气候联合研究与实训中心,甘肃兰州730000 [2]兰州中心气象台,甘肃兰州730020 [3]中国气象局兰州干旱气象研究所,甘肃兰州730020

出　　处：《高原气象》2021年第5期1057-1070,共14页Plateau Meteorology

基　　金：甘肃省气象局气象科研项目(英才计划,Zd2021-01);甘肃省气象局创新团队项目(GSQXCXTD-2020-01)。

摘　　要：为了尝试建立天气尺度环流分型与中小尺度雷达特征的衔接,本文基于2010-2015年15次区域性短时强降水天气过程,提炼总结了甘肃河东地区高原槽东移型、副高边缘型、西北气流型3种主要的短时强降水环流形势配置,并分析了不同环流形势下中小尺度系统雷达回波结构、演变的共性特征。结果表明:(1)高原槽东移型的雷达回波常为NNE~SSW走向的中β尺度层积混合带状回波,与700 hPa冷式切变线右侧的低空急流轴走向和位置较为一致。带状回波多在陇东南地区形成,偏南风低空急流对其传播方向产生重要影响,使其在陇东南维持3~4 h,多则5~6 h,常伴有“列车效应”。回波质心低,暖云降水为主,降水效率高。(2)副高边缘型的雷达回波常为NE~SW走向的中β尺度窄带状回波,位于略比700 hPa冷式切变线超前的地面锋线附近。往往在冷空气侵入到甘肃中部地区时生成,随着冷锋快速的由西北向东南方向移动,移至陇东南附近时,逐渐演变为具有高原槽东移型的雷达回波特征,但其向东南方向的移动速度相比高原槽东移型快。(3)西北气流型的雷达回波较为分散,局地性很强,主要是中γ尺度块状回波,主要有短生命周期的单体生消和多个单体组织、合并、加强两种形式,对流单体的发展较前两类更旺盛,属于深对流型。In order to try to establish the connection between large-scale synoptic situation configuration patterns and the medium and small scale radar characteristics,15 regional short-term heavy precipitation weather processes from 2010 to 2015 in East Gansu Province are used.These short-term heavy precipitation synoptic situation configuration patterns are divided into three patterns:eastward moving plateau low trough pattern,edge of subtropical high pattern,and northwest airflow pattern according to the difference of the main influence system in the 500 hPa.The common characteristics of weather radar echo structure and its’evolution under different patterns are also analyzed.The results show that:(1)The radar echo of the eastward moving plateau low trough pattern is usually a mid-β-scale stratified mixed band echo of NNE-SSW trend,which is consistent with the trend and position of the low-level jet axis on the right side of 700 hPa cold shear line.The band echo is mostly formed in southeast Gansu,and the southerly low-level jet has an important influence on its propagation direction,which makes it maintain for 3~4 hours,even 5~6 hours,often accompanied by"train effect".The radar echo center of mass is low,warm cloud precipitation is dominant,and with high precipitation efficiency.(2)The radar echo edge of subtropical high pattern is usually a mid-β-scale narrow band echo of NE-SW direction located near the ground front,which is slightly ahead of 700 hPa cold shear line.This kind of radar echo is usually generated when the rapid moved cold air(cold front)intrudes into the central area of Gansu Province.When the cold front moves to the southeast of Gansu Province,the radar echo gradually evolves into the characteristics that of eastward moving plateau low trough pattern.However,its speed of moving southeast is faster than eastward moving plateau low trough pattern.(3)The radar echo of northwest airflow pattern is relatively scattered and localized,it is mainly a mid-γ-scale block echo.Either short life cycle convec

关 键 词：短时强降水 环流形势配置 中尺度系统 雷达回波特征 

分 类 号：P458.11[天文地球—大气科学及气象学]