1966-2017年贵州省降雨侵蚀力的时空分布特征

Spatial and Temporal Distribution Characteristics of Rainfall Erosivity in Guizhou Province During 1966-2017

[目的]分析贵州省1966—2017年降雨侵蚀力R值的时空演变规律,为评估该地区降雨对土壤侵蚀的防治、制定水土保持措施及农业生产规划提供参考。[方法]基于贵州省33个气象站点1966—2017年的日降雨资料,利用克里金插值法、经验正交函数(EOF)方法、Mann-Kendall检验、Morlet小波分析法等,对贵州省52 a的降雨侵蚀力R值的时空特征进行了分析。[结果]①EOF分析方法可以较好地解释降水侵蚀力的时空分布特征,其前两个特征向量累计贡献率达52%,揭示了贵州省降雨侵蚀力全局型和东西反向型两种典型的分布模态。分析特征向量所对应的时间系数可得,贵州省的降水侵蚀力主要表现为全省全年偏大、全省全年偏小、东大西小、东小西大4种类型;②贵州省降雨侵蚀力R值年内主要受汛期降雨影响,全省各县市汛期降雨侵蚀力R值均占全年总量的60%以上;③在年际变化上,降雨侵蚀力R值存在多突变的现象,1971—1981年突变频率最为频繁。通过周期检验发现其变化主周期为28 a,次周期分别为12 a和6 a。[结论]贵州省降雨侵蚀力的时空分布与降雨量的时空分布趋势近似,整体呈现南部大北部小,夏季大冬季小的趋势,在未来几年内降雨侵蚀力R值有上升的趋势。

[Objective]The spatial and temporal distribution of the rainfall erosivity,represented as R value,in Guizhou Province from 1966 to 2017 was analyzed to provide reference for evaluating the prevention and control of soil erosion due to rainfall.The goal was to formulate soil and water conservation and agricultural production development measures in the study area.[Methods]Based on the daily rainfall data from 33 meteorological stations in Guizhou Province during 1966—2017,Kriging,empirical orthogonal function(EOF),Mann-Kendall examination,and Morlet wavelet analysis were utilized to analyze the R value characteristics in Guizhou Province over 52 years.[Results]①EOF analysis well-explained the spatial temporal distribution characteristics of rainfall erosivity.The cumulative contribution rate of the first two eigenvectors reached 52%,revealing two typical distribution modes of rainfall erosivity in Guizhou Province:the whole region pattern and the east-west reverse pattern.According to the analysis of the time coefficient corresponding to the feature vector,the erosive force of rainfall in Guizhou Province was mainly manifested in four ways:the erosive force of rainfall was relatively large during the entire year,it was relatively small during the entire year,it was relatively large in the east and and small in the west,and relatively small in the east and large in the west.②From the perspective of the entire year,the R value in Guizhou Province was mainly affected by the rainfall in flood season,and the R value in all counties and cities in the province accounted for more than 60%of the entire year.③The R value had multiple mutations in its interannual variation.The mutation frequency was the maximum during 1971—1981.Through the cycle test,it was observed that the main cycle of the change was 28 years,and the subcycles were 12 years and 6 years.[Conclusion]The spatial distribution of rainfall and rainfall erosivity was similar in Guizhou Province.Rainfall erosion was generally small in the south and large in the north,and small in summer and large in winter.The rainfall erosivity should increase in the next few years.