黄土高原不同类型暴雨的降水侵蚀特征

PRECIPITATION AND EROSION CHARACTERISTICS OF RAIN-STORM IN DIFFERENT PATTERN ON LOESS PLATEAU

本文对黄土高原的三种类型暴雨的降水、侵蚀特征进行了统计分析，结果表明：Ａ型暴雨的雨量多为１０－３０ｍｍ，历时一般为３０－１２０ｍｉｎ，最大６０ｍｉｎ降雨量占总雨量的８５％－１００％；Ｂ型暴雨的雨量一般为３０－１００ｍｍ，降雨历时多在３ｈ－１８ｈ之间，最大６０ｍｉｎ降雨量占总雨量的３０％－７０％；Ｃ型暴雨的雨量一般为６０－１３０ｍｍ，历时大于２４ｈ，最大６０ｍｉｎ降雨量占总雨量的８％－２５％。三种类型暴雨的空间分布不均匀程度是Ａ型大于Ｂ型，Ｂ型大于Ｃ型，且Ａ型比Ｂ型、Ｃ型大得多。Ａ型暴雨是引起土壤侵蚀的主要暴雨，其侵蚀性降雨发生的比例占侵蚀性降雨总次数的５２．７％，其侵蚀量占总侵蚀量的６４％。在坡面和沟道小流域，７０％的极强烈侵蚀是由Ａ型暴雨产生的。

In this paper,the precipitation and erosion characteristics of three rainstrom types on the Loess Plateau are statistically analyzed.The results show that the individual rainfall amount of pattern A,pattern B and pattern C storm is generally 10-30mm,30-100mm and 60-130mm respectively,and the rainfall duration of the pattern A,B and C storm is usually 30-120minutes,3-18 hours and more than 24 hours,the proportion of maximum rainfall in 60 minutes in total amount is 85-100% of pattern A,30-70% of pattern B,and 8-25% of pattern C.The nonuniformity of spatial distribution of three strom types is pattern A more than pattern B,pattern B more than pattern C,and pattern A more than pattern B and C greatly.Pattern A is the main strom that causes soil and water loss,and it's proportion of erosive rainfall and soil loss in total is 52.7% and 64% respectively.In slope ,gully and watershed,70% of the extreme erosion is caused by pattern A strom. \ \