皇甫川流域51年降雨侵蚀力的时空变化

为了详尽研究皇甫川流域降雨侵蚀力变化规律,基于皇甫川流域及周边15个雨量站1954-2004年日降雨资料估算降雨侵蚀力R值,并借助Mann-Kendall非参数检验法和Kriging空间插值法对流域R值时空变化特征进行分析.结果表明：1）皇甫川流域降雨侵蚀力R值与总降雨量和侵蚀性降雨量的时空变化特征大体一致,自西北向东南逐渐增大,同时R值等值线自西北向东南逐渐稀疏;2）R值年内分布十分集中,7、8月R值之和占到全年的72.4％,5-9月R值占到全年的96％以上;3）15个站点的R值变化趋势不同,9个站点R值呈增大趋势,其中仅2个站点增大趋势显著,而其余6个站点的R值呈减小趋势,其中也仅有2个站点减小趋势显著,对整个流域而言,51年间流域降雨侵蚀力R值与降雨量和侵蚀性降雨量变化一致,呈现不显著的减小趋势.

Spatial and temporal variation characteristics of rainfall erosivity in Huangfuchuan Watershed over 51 years

In order to elucidate the variation rule of rainfall erosivity （R） in Huangfuchuan Watershed,R value was estimated from 1954 to 2004 based on the daily rainfall data of 15 precipitation stations in Huangfuchuan Watershed,and the spatial and temporal variation of R was analyzed by Mann Kendall nonparametric tests and Kriging space interpolation method.The results are shown as follows.1） The characteristics of spatial and temporal variation of R value were generally consistent with those of total rainfall and erosive rainfall; spatially,R value decreased and the contour lines of R value thinned from southeast to northwest.2） From the temporal point of view,R value was concentrated from May to September,R value during this period accounted for more than 96％ of the total annual R value; especially from July and August,R value amounted to 72.4％ of the total annual R value.3） Annual R value at nine stations had an increasing trend,but only at two stations such trend was significant over 51 years,while it had a deceasing trend at the other six stations and also only at two stations this decreasing trend was significant over 51 years.For the whole Huangfuchuan Watershed,the change of R value was consistent with the variation of rainfall and erosive rainfall,and showed an insignificant trend of decreasing over 51 years.