日照市降雨侵蚀力时空分布特征

为掌握山东省日照市降雨侵蚀力时空分布特征,提高日照市水土保持规划与决策的科学性,利用日照市水利局雨量遥测系统61个雨量站点2005-2014年日降雨资料计算降雨侵蚀力,并运用Excel 2013、ArcGIS 10等工具分析日照市降雨侵蚀力的时空分布特征.结果表明:1)从年度变化来看,日照市站均年度降雨侵蚀力最大值(2008年)是最小值(2014年)的2.90倍,站均汛期降雨侵蚀力最大值(2007年)是最小值(2014年)的3.74倍.从月度变化来看,降雨侵蚀力主要集中在5-9月,尤其集中在7-8月.2)从空间分布来看,各站点年均降雨侵蚀力、汛期降雨侵蚀力呈现东南沿海地区较高、内陆地区较低、中部地区最低的特征,变化范围分别在2 942.07 ～4 921.45、2 694.36～3 921.78 MJ· mm/(hm2·h·a)之间,分区县看,岚山区最高,东港区次之,莒县和五莲县较低;各月的降雨侵蚀力重点也不尽相同.3)从时间变异来看,站均年度降雨侵蚀力变化范围在1 831.55 ～5 306.12 MJ·mm/(hm2·h·a)之间,均值、中值分别为3 826.01、4 053.62 MJ·mm/(hm2·h·a),标准差1 089.46MJ·mm/(hm2·h·a),变异系数28.48％;站均月度降雨侵蚀力变化范围在1.23 ～1 171.93 MJ·mm/(hm2·h·a)之间,均值、中值分别为318.83、61.51 MJ·mm/(hm2·h·a),标准差397.99 MJ· mm/(hm2·h·a),变异系数124.83％.4)从空间变异来看,各站年均降雨侵蚀力变化范围在2 755.23 ～5 061.15 MJ·mm/(hm2·h·a)之间,均值、中值分别为3 826.01、3 730.97 MJ·mm/(hm2·h·a),标准差512.81 MJ·mm/(hm2·h·a),变异系数13.40％.本研究结果可为日照市水土保持规划与决策、土壤侵蚀预报等提供参考.

Spatial and temporal variations of rainfall erosivity in Rizhao City

[Background] The Rizhao City,located in the southern coast of Shandong province,is northern rocky mountain soil and the national key harnessing area of Yimeng Mountains and Taishan Mountain,China.However,there are few studies on the soil erosion in the region,and no detailed research on the rainfall erosivity has been carried out specifically for Rizhao City scale.[Methods] In order to investigate the spatial and temporal variations of rainfall erosivity in Rizhao City and improve the scientific nature of soil and water conservation planning and decision-making,we used the daily rainfall data of 61 rainfall stations in Rizhao City from 2005 to 2014 to calculate the rainfall erosivity by the daily rainfall erosivity model,and analyzed the spatial pattern with the help of ArcGIS10 and the temporal variation and the correlation between rainfall,erosive rainfall and rainfall erosivity by virtue of Excel 2013.[Results] 1) For the temporal variability,the annual rainfall erosivity ranged from 1831.55MJmm/(hm2·h·a) to5306.12 MJ·mm/(hm2·h·a),the maximum value(2008) of the average annual rainfall erosivity was 2.90 times of the minimum (2014),and the maximum value (2007) of the rainfall erosivity in flood season was 3.74 times of the minimum (2014).The monthly rainfall erosivity per station was in the range of 1.23 MJ·mm/(hm2 ·h·a) to 1 171.93 MJmm/(hm2 ·h·a),the rainfall erosivity was concentrated from May to September,especially from July to August.2) For the spatial variations,the average rainfall erosivity yearly and in flood season generally increased from inland areas to southeast coastal areas,and the lowest in the central region.Comparing them at the county scale,the highest of the average annual rainfall erosivity was in Lanshan,and then Donggang,the lowest was in Juxian and Wulian.The average annual rainfall erosivity in each station was from 2 755.23 MJ·mm/(hm2·h·a) to 5 061.15 MJmm/(hm2 ·h·a),the average and the median was 3 826.01 MJ·mm/(hm2·h· a) and 3 730.97 MJ· mm/(hm2 · h ·a),respectively,and the standard deviation was 512.81 M J· mm/(hm2· h· a),and the variability coefficients was 13.40％.[Conclusions] The spatial distribution pattern of soil erosion in Rizhao City is not exactly matched with the spatial distribution of rainfall erosivity.In addition to the influence of rainfall erosivity,regional soil erosion is closely related to terrain,soil,vegetation and other factors.To strengthen the research on the comprehensive influence of various factors on soil erosion should be the direction of next step.The results can provide a reference for soil and water conservation planning and decision-making and prediction of soil erosion in Rizhao City.