摘要
利用2006-2021年贺兰山东麓地区23次暴雨过程,对比分析了一般暴雨(50~100 mm)、大暴雨(100~200 mm)、特大暴雨(200 mm以上)等3种不同量级暴雨过程的环流特征,建立了分级暴雨的天气学概念模型.结果表明:(1)暴雨期间中高纬为西风平直气流,暴雨区处于四股气流的交汇区:200 hPa偏西气流、500 hPa西南气流、700 hPa偏南气流、850 hPa东南气流,高低层均受高低空急流影响,量级上的差异主要来自南亚高压、西太平洋副热带高压(以下简称副高)、低空急流的位置、强度导致的低层温湿、热动力强迫、大气层结稳定度的不同.(2)中层700~500 hPa斜压性特征最明显,低层875~700 hPa次之;一般暴雨过程的斜压性最强,特大暴雨最弱.(3)影响一般暴雨过程的西风带锋面系统最活跃,随着冷锋过境,动力抬升增强,但副高和低空急流最弱最南,湿层最厚、暖云层最薄,K指数、SI、BLI等对流参数值最小,导致低层温湿、热力强迫和大气层结不稳定最弱,以锋区降水为主,暴雨量级小、对流弱.(4)影响大暴雨过程的冷暖空气势力相当,动力强迫较弱,但副高和低空急流偏北,低层温湿、热力强迫和大气层结不稳定较强,K指数、SI、BLI等对流参数值较大,锋面对流降水和锋区层云降水形成的暴雨持续时间长、范围广、量级较大、对流较强.(5)影响特大暴雨过程的南亚高压、副高、低空急流最强最北,低层高温高湿高能和强上升运动使得"上干下湿"的大气层结不稳定异常强烈,湿层最薄、暖云层最厚,CAPE、K指数、高低层垂直风切变和温差等对流参数是一般和大暴雨过程的1~3倍,低空急流北上西进与贺兰山地形结合,在东坡山区形成局地性强、时间短、量级大的强对流暴雨.
In this study,the rainstorm processes are classified into ordinary rainstorm(50~100 mm),heavy rainstorm(100~200 mm)and extraordinary rainstorm(more than 200 mm)according to the accumulated rainfall of the rainstorm process.Then,based on 23 rainstorm processes in the eastern foot of the Helan Mountain from 2016 to 2021,the circulation characteristics of different grades of rainstorms are investigated and the corresponding conceptual models are established.The results show that during the rainstorm processes,the westerlies prevail in middle-high latitudes.The rainstorm area is controlled by four airflows,i.e.the 200 hPa westerly airflow,the 500 hPa southwesterly airflow,the 700 hPa southerly airflow and the 850 hPa southeasterly airflow.There is high-level jet and low-level jet in the high and low levels,respectively.The different grades of rainstorms are mainly caused by the different locations and intensities of the South Asia high(SAH)and the Western Pacific Subtropical High(WPSH).The difference in SAH and WPSH can result in the differences in low-level temperature and humidity,and the stability of atmosphere.The baroclinity is the strongest in the middle levels(700~500 hPa),and is relatively weak in the low levels(875~700 hPa).The baroclinity is the strongest for ordinary rainstorm and the weakest for extraordinary rainstorm.For ordinary rainstorm processes,the fronts in the westerlies are the most active,the WPSH is the weakest and southmost,the wet layer is the thickest,the warm cloud layer is the thinnest,and the low-level thermal forcing and atmospheric instability is the weakest.For heavy rainstorm processes,the dynamic forcing is weaker,the WPSH and low-jet is more northward,the lowlevel thermal forcing and atmospheric instability is relatively strong,the values of convective parameters are relatively large,and the duration,area and magnitude of rainstorm are relatively large.For extraordinary rainstorm processes,the SAH,WPSH and low-level jet are the strongest and northmost,the atmospheric instability is
作者
陈豫英
苏洋
张一星
姚姗姗
杨银
CHEN Yuying;SU Yang;ZHANG Yixing;YAO Shanshan;YANG Yin(Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions,CMA,Yinchuan 750002,Ningxia,China;Ningxia Key Laboratory of Meteorological Disaster Prevention and Mitigation,Yinchuan 750002,Ningxia,China;Ningxia Meteorological Observatory,Yinchuan 750002,Ningxia,China)
出处
《高原气象》
CSCD
北大核心
2022年第5期1161-1174,共14页
Plateau Meteorology
基金
国家自然科学基金项目(41965001)
宁夏回族自治区科技创新领军人才培养工程项目(2021GKLRLX05)。
关键词
分级暴雨
斜压性
环流形势
热动力特征
概念模型
Different grades of rainstorms
baroclinicity
circulation situation
thermal and dynamic features
conceptual model
