高寒草甸草原地表径流的若干特征分析

目的]揭示高寒草甸草原降水特性、土壤水分对草地地表径流和水土流失的影响。方法]利用高寒牧区海北牧业气象试验站2005年9月~2007年10月观测的天然草地地表径流与大气降水、土壤水分及植被覆盖资料,分析了该地表径流的特征。结果]高寒草甸草原年平均径流系数为0.18%,各季地表径流夏季>秋季>春季,分别占年总径流量的57.3%、36.0%和6.7%,冬季无地表径流;年水土流失量主要由几次大降水造成;地表径流量与降雨量呈明显的线性正相关关系,与30 min最大雨强表现出指数函数关系,与0~20cm表层的土壤水分呈现显著的正相关关系。结论]为高寒草甸草原水旱灾害的综合防治和实现水资源的可持续利用提供科学依据。

Some Characteristic Analysis on Surface Runoff of Alpine Meadow Grassland

Objective] The aim was to reveal the effect of precipitation characteristics and soil moisture in alpine meadow grassland on surface runoff and soil and water loss in grassland.Method] The feature of the surface runoff was analyzed by using the data of surface runoff in natural grassland and atmospheric precipitation,soil moisture and vegetation cover,which were observed by Haibei Meteorology Experiment Station of Stockbreeding of alpine pasturing area from Sep.2005 to Oct.2007.Result] The annual mean runoff coefficient of alpine meadow grassland was 0.18%,the surface runoff of each season in order was summer > autumn > spring,accounted for 57.3%,36.0% and 6.7% of annual total runoff resp.,and there was no surface runoff in winter.The yearly soil and water loss volume was mainly caused by several large precipitation,the volume of surface runoff showed a obviously positive correlation with the rainfall,and exponential function with 30 min of maximum rain intensity,and a significantly positive linearity correlation with soil moisture in 0～20 cm surface.Conclusion] The study provided the scientific basis for integrated control of flood and drought disasters in alpine meadow grassland and for sustainable utilization of water resource.