1961-2020年沂蒙山区降雨侵蚀力时空变化特征

Spatiotemporal Variation Characteristics of Rainfall Erosivity in Yimeng Mountain Area from 1961 to 2020

为了分析沂蒙山区降雨侵蚀力的时空变化特征,利用沂蒙山区20个国家气象站1961—2020年的逐日降雨数据,采用日降雨侵蚀力模型、Mann-Kendall趋势/突变检验法、累积距平法、小波分析、反距离加权插值(IDW)等方法进行了系统的研究。结果表明:沂蒙山区年均降雨侵蚀力为5081.59(MJ·mm)/(hm 2·h·a),且年际变化呈现波动上升的变化趋势;年降雨侵蚀力存在22 a的主周期和7 a的次周期;降雨侵蚀力年内多集中在汛期6—9月份,占全年的84.15%;除秋季外,春季、夏季和冬季的降雨侵蚀力均呈现上升的变化趋势;年均降雨侵蚀力空间上由东南向西北呈带状逐渐递减;各气象站变异系数的范围是0.32~0.53,地区差异比较明显,西部地区相对较大,南部地区相对较小。沂蒙山区降雨侵蚀力的时空分布特征与侵蚀性降雨分布基本一致,并且集中分布在汛期,因此要加强研究区汛期尤其是7月、8月份的水土流失防治工作,可为研究区水土流失的监测、预报及治理等提供决策依据。

In order to analyze the spatiotemporal variation characteristics of rainfall erosivity in Yimeng Mountain Area,a systematic research was carried out based on the daily rainfall data from 1961 to 2020 of 20 national meteorological stations.The study methods include the daily rainfall erosivity model,Mann-Kendall test,cumulative anomaly method,wavelet analysis and inverse distance weighted interpolation(IDW).The results are as follows.The average annual rainfall erosivity was 5081.59(MJ·mm)/(hm 2·h·a)in Yimeng Mountain Area,and the interannual variation showed a fluctuating upward trend.Annual rainfall erosivity had a main cycle of 28-year and a subcycle of 13-year.Rainfall erosivity mostly concentrated in the flood season from June to September,accounting for 84.15%of the whole year.And except autumn,rainfall erosivity in spring,summer and winter showed an upward trend.The annual rainfall erosivity decreased gradually from southeast to northwest.The variation coefficients of the rainfall stations had obvious regional differences,ranging from 0.32 to 0.53,which was relatively great in the western region and relatively small in the southern region.The spatiotemporal distribution characteristics of rainfall erosivity in Yimeng Mountain Area were basically consistent with the distribution of erosive rainfall.And the rainfall erosivity mainly concentrated in the flood season.So,the soil erosion control in the flood season,especially in July and August,should be strengthened.These results can provide important reference for the monitoring,prediction and treatment of soil and water losses in the study area.