【摘要】 研究了祁连山排露沟流域降水特征及对径流的影响.结果表明:降水的季节性强且分配不均匀,存在明显的干季(11月至翌年4月)和雨季(5—10月)之分;排露沟雨季降水占全年降水量的88%,占全年降水频数的70%;干季降水仅占全年的降水量12%,占全年降水频数的30%.降水事件主要以0~5 mm的降水为主,占全年降水事件的78.8%,占全年降水量的30%;0~10 d的降水间隔期出现的频率高达86.1%,占全年无降水期的55.5%.降水受海拔高度的影响明显,沿海拔梯度呈先增后减的趋势,降水的峰值出现在海拔3400 m的区域.径流受降水的影响,主要集中在雨季,占全年的95.6%,干季径流仅占4.4%.径流与日降水、旬降水及其雨季月降水显著相关,其复相关系数均<0.7.径流主要受降水量和前期降水的影响,对于前期无降水基础、雨量<20 mm降水过程,径流变化迟缓,而对于前期有一定降水基础,雨量>25 mm的降水过程,径流变化大.更多还原

【Abstract】 Precipitation is one of the key factors for hydrology and influences the runoff producing of a mountain ecosystem in arid and semiarid areas.Analyzing the characteristics of precipitation and its effects on runoff in the recent years in Pailugou catchment of Qilian Mountains reveals: 1)Precipitation exhibits a high seasonality,with an irregular distribution,There are two distinct seasons,a rainy season(from May to October) and a dry season(from November to April of the next year).The percentage of precipitation and its frequency are 88% and 70% in the rain season and 12% and 30% in the dry season,respectively.2) On average,78.8% of all the precipitation events and 30% of the annual precipitation are ≤5mm,and 55.5% of annual dry period and 86.1% of dry day’s frequency of different length are ≤10 days.3) Under the effects of altitude,the precipitation from 2600 m to 3 400 m increases,and then decreases with altitude,with a maximum at the altitude of 3 400 mm.4) Runoff is mainly controlled by precipitation and concentrated in the rainy season.The percentage of runoff is 95.6% in the rain season and 4.4% in the dry season.5) The relationships between runoff and daily precipitation,ten-day precipitation and monthly precipitation in the rain season are evident(R2=0.272,0.642,0.569).6) Runoff is mainly dependent on precipitation size and preceding precipitation process,and the runoff has a gently variance with precipitation below 20 mm without preceding precipitation;There is a high variance with a preceding precipitation over 25 mm.更多还原