海南省东方市60年来降雨量及降雨侵蚀力变化趋势

Trends of Precipitation and Its Erosivity over Last 60 Years in Dongfang City of Hainan Province

[目的]分析海南省东方市降雨量、侵蚀性降雨量及降雨侵蚀力在不同时间尺度上的趋势变化及其相关性,为该区生态环境建设、水土流失治理及土壤侵蚀机理研究提供科学支持。[方法]根据该地区1956-2015年60a的逐日降雨量数据资料,采用变异系数、趋势系数和气候趋势率分析不同时间尺度的降雨、侵蚀性降雨和降雨侵蚀力的变化趋势。[结果](1)东方市1956—2015年60a来年均降雨量、年均侵蚀性降雨量、年均降雨侵蚀力分别为982.9±36.9mm,816.1±37.6mm和9 441.7±554.2 MJ·mm/(hm^2·h·a),变异系数分别为29.1%,35.7%,45.5%。(2)60a来降雨量、侵蚀性降雨量及降雨侵蚀力年际变化均呈一定的增加趋势,趋势系数分别为0.129,0.156,0.198。季、月尺度上变化差异较大,但总体变化格局相似,均呈单峰型分布。(3)降雨量、侵蚀性降雨量及降雨侵蚀力两两之间有极强的线性相关性,且乘幂方程较线性回归方程能更好的反映两两之间的关系。[结论]60a来降雨量、侵蚀性降雨量、降雨侵蚀力均呈现较明显的年际增加趋势,且两两之间呈幂函数关系。

[Objective]The temporal trends of rainfall,erosive rainfall and rainfall erosivity in Dongfang City of Hainan Province from 1956 to 2015 were analyzed to provide scientific support for the study of ecological environment construction,the soil erosion and soil erosion mechanism.[Methods]Based on the daily rainfall data from meteorological stations in Dongfang City from 1956 to 2015,indexes of coefficient of variation,trend coefficient and climate tendency rate were used toanalyze the trends of rainfall,erosive rainfall and rainfall erosivity in different time scales.[Results]（1）The average annual rainfall,the average annual erosive rainfall and the average annual rainfall erosivity in Dongfang City were 982.9 mm,816.1 mm and 9 441.7 MJ·mm/（hm^2·h·a）,respectively.Their coefficients of variation were 29.1% ,35.7% and 45.5% ,respectively.（2）Over the past 60 years,the annual variations of rainfall,erosive rainfall and rainfall erosivity all showed increase trends,with coefficients of 0.129,0.156,0.198.At seasonal and monthly scales,though big differences existed for all of the three rainfall indicators,the overall pattern of change was similar,that was a unimodal distribution.（3）There were a strong linear correlations among rainfall,erosive rainfall and rainfall erosivity,and also power function can reflect their relationships better than the linear one.[Conclusion]Over the past 60 years,rainfall,erosive rainfall and rainfall erosivity all showed obvious inter-annual trends of increase,they can be described well with power function among two of the three variables.