黄丘一区小流域暴雨特性研究

<正> 多年来,利用实验小流域雨量站网观测资料,我们对黄土丘陵沟壑区第一副区暴雨特性进行了分析研究,以便为小流域暴雨洪水计算及流域产沙数学模型的建立提供科学依据。 西太平洋副热带高压是影响本区暴雨的重要天气系统,故暴雨多发生在副热带高压西伸北进的时期。造成本区暴雨的天气尺度系统有西北涡和西风槽等。西北涡是造成夏季降水的重要天气系统,一般西北涡都能在本区造成暴雨,有一部分还能引起大暴雨。西风槽在传播过程中沿途都有不同程度的

Study on the Characteristics of Heavy Rain in a Small Watershed in the First Subregion of the Gullied Hilly Loess Region

This first subregion in the gullied hilly loess region belongs to typical continental climate. The annual average precipitation in this region is 400 -500mm, and the precipitation mainly "ocncentrates from July to September, amounting to about three quarters of the total annual precipitation . Heavy rain in this area is characterized by short duration,high intensity and highly concentrated temporal distribution. Intensity of rainstorm has the relationship with the duration for surface runoff to begin to take place as i=2.206t~(-0.762),and has the relationship with the impact of rain and the duration of rainfall as i=Sp/tβ. Through analysing the observed data, the authors obtained the criteria determining rain -storm causing erosion in different time intervals with 60 minutes of duration and related indexes about the calculation of intensity of the heavy rain.