晋西黄土高原降雨侵蚀力研究

降雨侵蚀力R值,是判断土壤侵蚀的最好指标,也是建立土壤流失预报模型最基本的因子之一。本文通过对大量实测资料进行分析,确定出适合于晋西黄土高原降雨侵蚀力R的最佳计算指标R=∑EI10,并根据这一计算指标和417站年、3679次侵蚀性降雨资料,应用微机求得了晋西黄土高原4.6万多km~2的多年平均R值为125.81J/(m~2·h)。晋西黄土高原降雨侵蚀力的年际变化幅度很大,最高年可达575.65J/(m~2·h),最低年只有3.85J/(m~2·h),一年中降雨侵蚀力R值以7、8两个月为最高,可占年R值的76.87%。在空间分布上,南部R值较大,北部偏小。

Study on Erosive Force of Rainfall on Loess Plateau in Western Shanxi Province

The value of R, erosive force of rainfall, is the best index judging soil erosion, and is also one of the basic factors used for setting up prediction model of soil loss. Through analysing data measured on the spot, the best adapted to loess plateau in Western Shanxi Province for calculating the erosive force of rainfall is defined as: R=EI10.According to this index and the data of rainfall from 417 station years, as well as 3679 events of erosive rainfall, the average annual value of R in loess plateau in Western Shanxi Province ( covering an area of more than 46 thousand km2) is 125.81 J/(m2·h). The annual variation of erosive force of rainfall in this area is very large with a maximum of R 575.65 in a year to a minimum of R 3.85 in a year. For the distribution in a year, the value of R is higher in July and August, equivalent to 76.9% of the annual value and for the spatial distribution, the value in southern area was higher than that in northern area.