摘要
基于临夏州2006—2018年4—9月自动气象站逐日小时降水量,在传统降水百分位法、Z指数法和平方根变换法3种方法中,确定了短时强降水阈值的最佳计算方法,在此基础上分析临夏州短时强降水的时空分布特征。平方根变换法确定的临夏州短时强降水阈值为14.6 mm·h^(-1)。临夏州短时强降水空间分布表现为自中南部分别向西北和东南减少,短时强降水年平均出现次数为7.3次,2018年出现次数最多;7—8月短时强降水出现频次最多,占短时强降水总频次的81.1%,8月达到最高峰,占总频次的55.8%;短时强降水日变化呈4峰分布,短时强降水主要出现在18:00—23:00,占短时强降水总频次的55.8%;小时最大降水量为55.8 mm,出现在22:00;短时强降水持续时间为1 h的占90.5%,同一时次出现1站次短时强降水的占93.3%,临夏州短时强降水多为阵发性,且空间分布多为孤立零散。
Based on hourly precipitation data from April to September during 2006-2018 in Linxia of Gansu Province,the best method of threshold value caculation of short-time heavy rainfall was determined among the traditional precipitation percentile method,Z index method and square root transformation method.The spatial and temporal distribution characteristics of short-time heavy rainfall in Linxia was analyzed.The results show that the short-time heavy rainfall threshold determined by the square root transformation method was best,and it was 14.6 mm·h^(-1).The threshold decreased from the central-southern part to northwestern and southeastern parts,respectively,and the annual average frequency of short-time heavy rainfall was 7.3 times,and it was most in 2018.The short-term heavy rainfall was much concentrated in July and August,accounting for 81.1%of the total frequency of short-time heavy rainfall.The maximum short-term heavy rainfall mainly occurred from 18:00 to 23:00,accounting for 55.8%of the total frequency of short-time heavy rainfall.Short-time heavy rainfall lasting 1 hour accounted for 90.5%.At the same time,the cases of short-time heavy rainfall occurring at one station accounted for 93.3%.The occurrence of short-time heavy rainfall in Linxia was mostly episodic,and the spatial distribution was mostly isolated and scattered,and occurrence of short-time heavy rainfall tended to increase in frequency.
作者
杨振鑫
祁萍
孙磊
崔小平
赵月兰
YANG Zhenxin;QI Ping;SUN Lei;CUI Xiaoping;ZHAO Yuelan(Hezheng Meteorological Station of Gansu Province,Hezheng 731200,Gansu,China;Linxia Meteorological Bureau of Gansu Province,Linxia 731100,Gansu,China;Yongjing Meteorological Station of Gansu Province,Yongjing 731600,Gansu,China)
出处
《干旱气象》
2021年第4期563-568,共6页
Journal of Arid Meteorology
基金
甘肃省气象局气象科研项目人才专项(GSMArc2019-29)资助。
