摘要
利用常规观测、FY-2G、多普勒天气雷达、风廓线雷达、地基微波辐射计资料和NCEP/NCAR(1°×1°)再分析资料对2015年6月9日、6月27日和2016年10月2-3日乌鲁木齐三次典型暴雨过程(分别简称为过程1、过程2和过程3)的中尺度影响系统和大气垂直结构进行分析。结果表明:降水历时短且有短时强降水出现的过程1和过程2为强对流型暴雨,分别产生在高压脊前西北气流和低值系统前部西南气流中;历时较长且相对平稳的过程3为平稳型暴雨,出现于槽前偏西气流中。强对流型暴雨的大气层结不稳定性更强、低层大气更湿,对暴雨中短时强降水的出现更为有利,此类暴雨是由相对孤立、尺度小、生成和发展迅速且生命史短的β-中尺度对流云团及尺度小、生消快、移动迅速的γ-中尺度对流单体直接造成,且伴有中低层风速辐合和低层辐合高层辐散;平稳型暴雨则是由持续时间长且尺度大的层积混合云团、雷达回波及切变线直接造成。风廓线雷达水平风场资料和地基微波辐射计相对湿度资料分别能够细致刻画和监测乌鲁木齐两类暴雨过程水平风场和大气相对湿度演变特征。暴雨开始前,低层风场和高层风场随高度分别出现顺时针和逆时针旋转,低层暖平流和高层冷平流增强了大气的不稳定性;暴雨临近前0. 5~1 h,不同高度上风速的明显增长和相对湿度的剧烈发展可作为暴雨即将开始的预警;暴雨过程中垂直风切变明显且水汽饱和区以波动形式发展;强对流型暴雨水平风场和相对湿度变化更为剧烈,同时,水汽饱和区发展到暴雨过程中最高位置时,短时强降水产生。
Based on the conventional observational data,the TBB data of FY-2 G satellite,data of Doppler weather radar,wind profiler radar,ground-based microwave radiometer,and NCEP/NCAR reanalysis data with 1°×1° spatial resolution,the mesoscale system and atmospheric vertical structure of three typical heavy rain processes occurred on 9 June,27 June 2015 and from 2 to 3 October 2016(referred to as Process 1,Process 2 and Process 3,respectively)in Urumqi were studied. The results are as follows:Process 1 and Process 2 were the strong convective storm,which were generated in the southwest airflow before the high-pressure ridge and the southwest airflow in the front of the low-value system with short-term heavy precipitation,respectively;Process 3 was the steady rainstorm,which was the longer and smoother occurred in the westward airflow in front of the trough. Process 1 and Process 2 were more favorable for the occurrence of short-term heavy precipitation during heavy rain due to more unstable and more humid at the lower atmosphere than Process 3. The strong convective storm were caused by β-mesoscale convective clouds,which were relatively isolated,small in scale,rapid in generation and development,and short in life history as well as the γ-mesoscale convective system,which were small in scale,fast in growth and rapid in movement,and there were convergence of wind speed at intermediate and low-level and convergence at low-level and divergence at high-level in radial velocity;The steady rainstorm was caused long-term and large-scale laminated hybrid cloud,echoes of stratified hybrid cloud and shear lines.Wind profiler radar and microwave radiometer could meticulously describe the evolution of wind field and humidity during heavy rain,the high and low wind fields showed reverse and clockwise rotation with height,and the cold and warm advection enhanced the instability of the atmosphere before the start of heavy rain;When the rainstorm is approaching 0. 5~1 h,the obvious increase of wind speed at different altitudes and the sharp development of relative humidity could be used as the early warning for the beginning of heavy rain;vertical wind shear was obvious during the rainstorm and the water vapor saturation zone developing in the form of fluctuations;horizontal wind field and relative humidity change more severely during the strong convective rainstorm. At the same time,when the water vapor saturation zone developing to the highest position in the heavy rain process,short-term heavy precipitation occurred.
作者
曾勇
杨莲梅
ZENG Yong;YANG Lianmei(Institute of Desert Meteorology,China Meteorological Administration,Urumqi 830002,Xinjiang,China;Center for central Asia Atmosphere Science Research,Urumqi 830002,Xinjiang,China)
出处
《高原气象》
CSCD
北大核心
2020年第4期774-787,共14页
Plateau Meteorology
基金
新疆气象局科学技术研究面上项目(MS201807)
中国气象局沙漠气象科学研究基金项目(Sqj2016016)
中央级公益性科研院所基本科研业务费专项资金项目(IDM2019001)
国家重点研发计划专项(2018YFC1507104)。
关键词
乌鲁木齐
暴雨
中尺度系统
大气垂直结构
Urumqi
heavy rain
mesoscale system
atmospheric vertical structure
