基于日降雨数据的广东省降雨侵蚀力初步分析

ANALYSIS OF RAINFALL EROSIVITY BASED ON THE DAILY PRECIPITATION IN GUANGDONG PROVINCE

降雨侵蚀力是反映降雨引起土壤侵蚀的潜在能力.利用广东省26个基本气象站点的多年逐日降雨资料,计算分析了降雨侵蚀力的空间分布和时间变化特征.结果表明,广东省降雨侵蚀力的空间分布呈沿海地区向内部山区逐渐递减趋势,分布特征与多年平均降雨量分布类似;降雨侵蚀力主要集中于4～9月份(雨季),占全年的84.8%,根据季节分布特征,可划分为三个类型区:第一类型区分布于粤北、粤东北、粤西北的内陆山区,第二类型区分布于粤中、粤东和粤西部分地区,第三类型区分布于广东省南端的电白、吴川和雷州半岛地区,各类型区之间的季节分布有明显差异;在降雨侵蚀力的年际变化上,1961～2001年间大部分地区呈现不同程度的正趋势,最大趋势系数(r)可达0.326,其年际变化特征与降雨量和降雨强度相关密切.

Rainfall erosivity reflects the potential ability of soil erosion by the rainfall. In order to analyze the temporal change and spatial distribution of rainfall erosivity, the annual daily rainfall data from 26 meteorological stations in Guangdong province were used for computation. The result show that the spatial distribution of rainfall erosivity has the trend of decreasing from the coastal regions to the inland mountainous regions that is similar to the distribution of annual rainfall. The rainfall erosivity concentrates in rainy season （April to September）, which contributes 84.8% of the year. Based on the temporal distribution, the rainfall erosivity can be distributed in 3 types （1; 2; 3） which are obviously different： （1） Distributing in inner mountainous regions of northern, northeastern, and northwestern; （2） Distributing in middle, eastern and western; （3） Distributing in Dianbai, Wucuan, and Leizhou Peninsula, which is in the south. The annual change of rainfall erosivity shows the positive trends in most parts of Guangdong between 1961-2001, which correlates to the rainfall and rainfall intensity. The max trend coefficient（r） is 0.326.