摘要
前期有效降水量是泥石流预报的重要参数之一,对不同类型泥石流的形成有不同的影响形式,对土力类泥石流的形成主要是影响泥石流形成区土体的土壤含水量。在每次前期降水增加的土壤含水量和其有效降水量遵循相同衰减规律,以及每次前期降水的有效降水量和其增加的土壤含水量衰减过程都是相互独立的假设条件下,通过分析土壤含水量随时间的变化关系,可以得到前期有效降水量与前期降水量随时间的变化关系,从而可以确定前期有效降水量。通过对云南蒋家沟降水和土壤含水量的实际观测,对这个关系进行了分析研究,并利用最小二乘法得出了前期有效降水量的计算公式。
Effective antecedent rainfall （EAR）, one of important factors for debris flow forecast, has different ways of influencing debris flow initiation for different types of debris flow. For soil-mechanics-typed debris flow, EAR impacts its initiation by changing the soil moisture content, and for hydromechanics-typed debris flow, EAR impacts its initiation by increasing the surface runoff. For this reason, the methods of determining EAR for different types of debris flows are different. The method for the former type of debris flow is discussed in this paper. Under the assumptions that soil moisture content due to antecedent rainfall decays in the same way as EAR, and that the decays for different events are mutually independent, the variation of EAR can be carried out through analyzing the variation of soil moisture content; the EAR for debris flow forecast can then be determined. The decaying of soil moisture content has been analyzed according to the field observation of rainfall and soil moisture content in Jiangjia Gully in the province of Yunan, where debris flows are caused by soil mechanical changing triggered by rainfall. Based on the observation and analysis, the formula of calculating EAR for Jiangjia Gully is made out with least-squares procedure.
出处
《山地学报》
CSCD
北大核心
2005年第4期453-457,共5页
Mountain Research
基金
中国科学院知识创新工程资助项目(KZCX3-SW-352)
国家杰出青年科学基金项目(40025103)
中国科学院成都山地所创新前沿项目(C3200307)资助~~
关键词
泥石流
预报
前期降水量
有效降水量
debris flow
forecast
antecedent rainfall
effective rainfall
soil moisture content
