基于Γ函数的祁连山葫芦沟流域湿季小时降水统计特征  

Study of Statistical Characteristics of wet Season Hourly Rainfall at Hulu Watershed with Γ Function in Qilian Mountains

作　　者：王磊[1,2] 陈仁升[1,2] 宋耀选[1,2] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所黑河上游生态-水文试验研究站,甘肃兰州730000 [2]中国科学院内陆河生态水文重点实验室,甘肃兰州730000

出　　处：《地球科学进展》2016年第8期840-848,共9页Advances in Earth Science

基　　金：国家重点基础研究发展计划项目"寒区流域水文过程综合模拟与预估研究"(编号:2013CBA01806);国家自然科学基金项目"黑河流域上游生态水文过程耦合机理及模型研究"(编号:91225302)资助~~

摘　　要：高山区降水主要集中在湿季（5～9月）,湿季小时降水的概率分布统计特征是研究山区降水分布的重要基础。选择祁连山中段典型流域为研究区,使用葫芦沟流域6个观测点2015年5～9月半小时降水数据,采用极大似然法对影响Γ分布函数的形状参数α和尺度参数β进行估计,并且对不同强度降水概率密度分布、累计概率密度以及降水概率与海拔和降水量关系进行分析。结果表明：形状参数α和尺度参数β呈明显负相关,形状参数α与小时平均降水量分布大致相同;在葫芦沟流域,除海拔因素外,局地地形也是影响降水再分配和降水概率分布的重要因素;在该流域,除降水事件增加外,1～3 mm/h强度降水概率随着海拔增加而增加也是降水量随海拔增加而增加的主要原因。The probability distribution of the wet season hourly precipitation is the important basis for the study of the precipitation distribution,especially in mountainous areas. Hulu watershed is the study area located in the upper reaches of Heihe River,Qilian Mountains. By adopting the maximum likelihood estimation,the shape parameter α and scale parameter β of 6 stations were obtained with observed wet season（ May to September） half hourly data,and different intensity precipitation probability density distribution,cumulative probability density and probability of precipitation and elevation and precipitation relationship were analyzed. The shape parameter α and scale parameter β is significantly negatively correlated,shape parameter α and average hourly precipitation distribution is consistent. Local topography is also an important factor to affect the precipitation redistribution and the probability distribution of precipitation in Hulu watershed. In addition to the increase of precipitation events,the probability of 1 ～ 3 mm mm / h precipitation increases with the altitude,which is the main reason for the increase of precipitation with altitude.

关 键 词：Γ函数 高海拔山区 湿季小时降水 概率密度 

分 类 号：P426.6[天文地球—大气科学及气象学]