陇东黄土高原旱区短时强降水的时空分布特征及地形影响研究  

Research on spatio-temporal distribution characteristics of short-term heavy rainfall and terrain influence in the Loess Plateau arid region of eastern Gansu

作　　者：杨丽杰 曹彦超 刘维成[2] 徐丽丽 张洪芬 孙子茱 YANG Lijie;CAO Yanchao;LIU Weicheng;XU Lili;ZHANG Hongfen;SUN Zizhu(Qingyang Meteorological Bureau of Gansu Province,Qingyang 745000,Gansu,China;Lanzhou Central Meteorological Observatory,Lanzhou 730020,China)

机构地区：[1]甘肃省庆阳市气象局,甘肃庆阳745000 [2]兰州中心气象台,甘肃兰州730020

出　　处：《干旱气象》2022年第6期945-953,共9页Journal of Arid Meteorology

基　　金：甘肃省自然科技计划资助项目(22JR5RM1045);甘肃省气象局气象科研项目(Zd2023-03、ZcMs2021-24);甘肃省气象局英才计划项目(2122rczx-04);甘肃省气象局研究型业务项目(Ms2021-09);庆阳市科技重大专项计划项目(QY-STK-2022A-071);庆阳市气象局科研项目(QY2022-1)共同资助。

摘　　要：利用陇东黄土高原旱区2013—2020年302个区域自动气象观测站逐小时降水数据、数字高程模型数据和欧洲中期天气预报中心ERA5再分析资料等,分析短时强降水时空分布特征及其与地形、地理因子的关系,并结合2021年一次极端短时强降水事件,总结地形的影响机制。结果表明:(1)陇东黄土高原旱区短时强降水主要集中在夏季,7月日数占比(35.9%)最多、极端性最强,8月次数占比(46.9%)最多、强度最强;雨强主要分布在22.0~31.0 mm·h^(-1),日变化呈多峰型特征,17:00(北京时,下同)至次日00:00最为活跃,次数占比为56.8%,且强度和极端性最强。(2)短时强降水次数和小时雨量极值空间分布极不均匀,前者东南多、西北少,且随着雨强增大骤减,高发区主要集中在河谷喇叭口地形区,而掌地也是30.0 mm·h^(-1)以上强降水高发区;后者中部小、东北与西南大,大值区主要分布在庆城东部—合水西部。(3)地理、地形因子对短时强降水次数影响显著,主要由地理位置贡献,而对极值无明显影响,地形强迫抬升并非是陇东黄土高原旱区短时强降水的主要影响机制。(4)山谷风环流及其诱发的地面中尺度辐合线是陇东黄土高原旱区河谷喇叭口地形区短时强降水形成的重要原因。Based on the hourly precipitation data from 302 regional automatic weather stations in the Loess Plateau arid region of east⁃ern Gansu from 2013 to 2020,digital elevation model data from shuttle radar topography mission and ERA5 reanalysis data of Euro⁃pean Centre for Medium-Range Weather Forecasts,etc.,the spatio-temporal distribution characteristics of short-term heavy rainfall are analyzed,and on this basis that the relationship between it and topography,geography factors is discussed.Then combined with an ex⁃tremely short-term heavy rainfall event in 2021,the influence mechanism of terrain is summarized.The results are as follows:(1)The short-term heavy rainfall mainly occurs in summer in the Loess Plateau arid region of eastern Gansu,and in July the proportion of short-term heavy rainfall days(35.9%)is the most and the extremity is the strongest,while in August the proportion of short-term heavy rain⁃fall times(46.9%)is the most and the rainfall intensity is the strongest.The rainfall intensity mainly ranges from 22.0 to 31.0 mm·h^(-1),and it shows a multi-modal diurnal distribution with the most active,strongest and most extreme from 17:00 BST to next 00:00 BST,whose proportion of times is 56.8%.(2)The spatial distribution of the occurring times and hourly precipitation extremum of short-term heavy rainfall events is extremely uneven.The occurring times is less in the northwest and more in the southeast,it decreases sharply with the increase of rainfall intensity,and the short-term heavy rainfall occurs frequently in the area with valley bell-mouth topography,moreover,the palm landform is also the high incidence area of heavy precipitation above 30.0 mm·h^(-1).The extremum is small in the middle and large in the northeast and southwest,the large value mostly distributes in eastern Qingcheng and western Heshui.(3)The in⁃fluence of geographical and topographic factors on occurring times of short-term heavy rainfall is significant,and its contribution comes from geographical location,while their in

关 键 词：短时强降水 时空分布 地形影响 陇东黄土高原旱区 

分 类 号：P463.213[天文地球—大气科学及气象学]