摘要
降雨是导致土壤侵蚀的主要动力因素,通用土壤流失方程(USLE)中降雨侵蚀力因子R反映了降雨气候因素对土壤侵蚀的潜在作用。为更精确估算降雨侵蚀力,以全国564个测站1971～1998年的逐日降雨资料为基础,采用一种新方法估算降雨侵蚀力,分析全国降雨侵蚀力空间变化特征。结果显示全国降雨侵蚀力的空间分布与降雨量近似,但降雨降雨侵蚀力取决于降雨量和降雨强度两个方面,因此二者的空间分布又存在许多差别。一般在降雨侵蚀力较小地区,降雨侵蚀力的年内分配非常集中,全国大部分地区降雨侵蚀力年际变化表现出正的趋势,江西和湖南等交界的部分地区为明显的正趋势中心。
Rainfall is the main dynamic factor that causes soil loss Rainfall erosivity factor in Universal Soil Loss Equation (USLE) shows the potential ability of the soil loss caused by rainfall Estimating the rainfall erosivity accurately is very significant to predict soil loss quantitatively and make soil and water conservation program Typical method of computing rainfall erosivity needs data of rainfall events, but this data is unreadily available In order to estimate rainfall erosivity more accurately and analyze the spatial distribution and temporal change of rainfall erosivity, an new method was adopted to compute the rainfall erosivity of china using daily rainfall data between 1971 and 1998 from 564 weather stations The distribution of rainfall erosivity has the trend of decreasing from southeast to northwest, which is similar to the distribution of rainfall However, the rainfall erosivity is influenced by rainfall amount and intensity, so there are a lot of difference between the distribution of rainfall and rainfall erosivity Moreover, the distribution of rainfall erosivity in china is different from actual distribution of soil loss in china The average annual rainfall erosivity exceeds the 10000 MJ·mm·hm-2·h-1 in south semitropical zone?north torrid zone and middle torrid zone where the soil loss is relative light, but the average annual rainfall erosivity is under the 2000 MJ·mm·hm-2·h-1 in all or most parts of the Loess Plateau where the soil loss is very serious In general, the seasonal distribution of average annual rainfall erosivity is very centralized in the regions where the average annual rainfall erosivity is relatively small The percentage of the sum of continual sixsemimonth rainfall erosivity to annual rainfall erosivity is over 80% in northwest and northeast regions in china, however the percentage in most parts of south of Changjiang River is under 60% The annual change of rainfall erosivity shows the positive trends in most parts of county and the rainfall erosivity increases 800 MJ·mm·hm-2·h-1 or more per 10 years for recent 30 years in the parts of Jiangxi and Hunan province There are a lot of difference between the annual changes of rainfall and rainfall erosivity because rainfall erosivity is influenced by rainfall amount and intensity
出处
《山地学报》
CSCD
2003年第1期33-40,共8页
Mountain Research
基金
国家自然科学基金(编号40171059)
北京师范大学青年科学基金资助~~
