1970-2019年大汶河流域降雨侵蚀力时空变化分析

Spatiotemporal Variation of Rainfall Erosivity in the Dawen River Basin During 1970-2019

研究大汶河流域降雨侵蚀力(R)对土壤侵蚀的影响,可为流域水保工作提供科学依据。以大汶河流域6个雨量站1970—2019年逐日降雨数据为基础,通过Mann-kendall趋势检验和突变检验、累积距平、小波分析、逆距离加权插值和泰森多边形等多种方法分析了大汶河流域降雨侵蚀力的时间与空间的分布特征。结果表明:大汶河流域1970—2019年年均降雨侵蚀力范围为1310.84~6721.53 MJ·mm/(hm^(2)·h·a),均值为3808.83 MJ·mm/(hm^(2)·h·a),年际变化比较剧烈且呈微弱下降趋势,存在着4~7 a,8~12 a,17~25 a共3类周期变化,突变年份为1979年;年内分布集中在6—9月,7月、8月尤为突出,四季的年际变化趋势为先上升后下降再到上升;空间上整体分布为中部>东部>西部,整个流域降雨侵蚀力的离散程度为东、西部较大,中部较小;降雨侵蚀力与海拔、降雨量在不同的地区上都有较强的相关性。大汶河流域降雨侵蚀力空间分布差异显著,年际存在周期性且变化显著,年内集中于7月、8月。因此,7月、8月水土流失的预防和控制尤为重要。

In order to study the influence of rainfall erosivity(R)as it relates to soil erosion in the Dawen River Basin,and provide a scientific basis for local water and soil conservation,a study was conducted on the daily rainfall data of six rainfall stations from 1970 to 2019.The temporal and spatial distribution characteristics of R was analysed by methods such as the Mann-Kendall trend test,catastrophe test,cumulative anomaly,wavelet analysis,inverse distance weighted interpolation and the Tyson polygon.The results showed that the annual average R from 1970 to 2019 ranged from 1310.84 to 6721.53 MJ·mm/(hm^(2)·h·a),with an average of 3808.83 MJ·mm/(hm^(2)·h·a).The inter-annual variation of R was drastic and showed a weak downward trend.There were three types of periodic changes of 4~7 years,8~12 years and 17~25 years,with a sudden change in 1979.The distribution of R was concentrated from June to September during the year,especially in July and August.The changing trend of R during the four seasons was at first rising,then falling,and then rising again.The order of R in its spatial distribution was central,then eastern and then western respectively.The dispersion degree of R is greater in the east and west and is lesser than that of the central.R was closely related to the altitude and rainfall in different zones.The spatial distribution of R in the Dawen River Basin varies significantly,with inter-annual cycles and dissimilitude,concentrated in July and August during the year.Taking everything into consideration,there is no doubt that the prevention and control of soil erosion in July and August is paramount.