1980-2013年闽西地区降雨侵蚀力时空变化特征

闽西地区是福建省土壤侵蚀重点防治区,为研究闽西地区降雨侵蚀力的时空分布格局,根据1980-2013年闽西地区9个站点的逐日降雨数据,利用日雨量模型来计算降雨侵蚀力,采用线性回归、气候倾向率、Mann-Kendall检验和反距离加权插值法(IDW)等方法对区域降雨侵蚀力的时空变化进行分析.结果表明:1)闽西地区多年平均降雨侵蚀力为9 504 MJ·mm/(hm2·h),与降雨量呈极显著正相关(P＜0.o1);2)空间上西高东低,与降雨量分布规律基本一致;3)降雨侵蚀力的年内分布主要集中在3-8月,占到全年的80.12％;4)1980-2013年期间研究区降雨量呈微下降趋势,而整体上降雨侵蚀力呈略微增加趋势,但未达到显著水平(P＞0.05),其中其在夏季呈现上升趋势,而在春秋冬3季呈现下降趋势;5)34年内降雨侵蚀力分别在1995和2002年发生突变.该研究可为该区域土壤侵蚀危险性评估和土壤侵蚀治理工作提供依据.

Spatial and temporal variations of rainfall erosivity on West Fujian during 1980 to 2013

Background] Rainfall erosivity is for assessing the potential ability of rainfall on soil erosion.A regional soil erosion prevention and controlling work have a guiding significance.Water erosion is one of the important forms of soil erosion in Fujian province.Methods] To study the spacetime distribution of West Fujian rainfall erosivity pattern,based on the 1980-2013 daily rainfall data of nine weather stations in West Fujian region and using the Daily Rainfall Erosion Force Model to calculate the rainfall erosion force,then methods of linear regression,climate tendency rate,Mann-Kendall test methods and the spatial interpolation methods were applied to analyze the spatial and temporal variations of rainfall erosivity.Results] 1) The range of annual rainfall erosivity in the West Fujian was 6 160-14 310 MJ·mm/(hm2 ·h) with an average value of 9 504 MJ·mm/(hm2 ·h),the amplitude of 8 150 MJ· mm/(hm2 ·h),average rainfall erosivity was very significantly and positively correlated with the average rainfall.2) There was a spatial distribution pattern of annual rainfall erosivity and it was greater in the western area and less in the eastern area of the studied area,rainfall erosivity of high value area was in the northwest and low value area was in the northeast.The spatial distribution of average annual rainfall erosivity was similar to that of average annual precipitation;nine counties of rainfall erosivity in ascending order,respectively:Ninghua ＞ Dongxing ＞ Guanyinqiao ＞ Zhongshan ＞ Yongding ＞ Shanghang ＞ Yangjiafang ＞ Zhangping ＞ Yong'an.3) The rainfall erosivity concentrated in rainy season (March to August),which contributed 80.12％ of the whole year. During the year the distribution curve of rainfall erosivity showed bimodal type,peak for June and August.Rainfall erosivity changed in a positive trend,including January,May,June,July,August,October,November,and December,which was the most obvious in June.Meanwhile,the declining trend of rainfall eruption included February,March,April,and September,which was the most obvious in March.4) The rainfall erosivity showed upward trend in summer,but downward trend in other periods.The annual change of rainfall erosivity indicated that rainfall and rainfall erosivity showed downward trends.Rainfall to changes in the rate of decline in 7.3 mm in every 10 years,and the climate rate of rainfall erosivity was 72.7 MJ· mm/(hm2· h· 10 a).5) The abrupt change of rainfall erosivity occurred in 1995 and 2002,respectively,and rainfall erosivity had a slight upward trend since 1995,and from 2002 it had the obvious downward trend.Conclusions] Soil erosion in the West Fujian is the key prevention area on soil and water erosion,and the government should increase attentions on it.The results of the study provide the basis for the regional soil erosion prediction,the regional risk assessment of soil erosion,and soil erosion management work.