Temporal Distribution Characteristics and Variation Trend of Rainfall Erosivity in the Core Area of Dongzhi Tableland
Rainfall erosivity reflects the potential ability of soil loss caused by rainfall and is an important factor in quantitative prediction of soil loss.Based on the daily rainfall data between 1951 and 2011 from Xifeng meteorological station,which is in the center of Dongzhi tableland,rainfall erosivity was estimated and its temporal distribution characteristics and variation trend were analyzed with the trend coefficient and Mann-Kendall test.The results showed that:① the annual rainfall erosivity value (R value) ranged from 706.9 to 3 200.6 MJ · mm · hm-2 h-1 · a-1,with an average of 1 634.7 MJ · mm · hm-2 · h-1 · a-1 in the past 61 years.The seasonal distribution of R value is a single peak,concentrating from July to September and taking 72.6％ of total annual R value.R value of July is the largest one among all months within a year which is 520.9 MJ · mm · hm-2 · h-1 · a-1 and takes 31.9％ of total annual R value.There is no erosive rainfall in winter (January,February and December) since 1954; ② The trend coefficients of annual,vernal,aestival and autumnal R value during 1951-2011 are 0.005,-0.104、0.054 and-0.016,which suggested that the trend of ascend or descend are not significant ; ③ The rainfall erosivity of the core area of Dongzhi tableland shows a change in variability in the past 61 years,which means that there is little change in average rainfall erosivity but the standard deviation (SD) and variation coefficient (CV) of the R value change significantly.The SD and CV of annual rainfall erosivity increased significantly (P =0.030 and 0.044 ＜ 0.05).Except for autumn,the SD of vernal and aestival rainfall erosivity increased by 38.5％ and 36.3％ respectively while the CV of vernal and aestival rainfall erosivity increased by 47.8％ and 11.0％ respectively.Although there were no significant increase of rainfall erosivity in the core area of Dongzhi tableland during 1951-2011,the increasing variability of rainfall erosivity may increase the risk of soil loss.
国家科技期刊平台
NSTL
万方数据
维普
