文章采用海河流域北系20个气象站1956年－2012年降水时间序列，从趋势、周期、突变和空间差异四个方面分析了该地区降水时空变化特征。结果显示：海河北系年降水以14.9 mm/10a的速度减少；降水具有多时间尺度下的显著差异特征：月尺度较平稳，仅10月、11月发生显著下降，5月、6月发生显著增加；季尺度上，春、秋季较平稳，夏、冬季呈现下降趋势；年降雨呈现28年显著周期，并且在20世纪80年代前后转入枯水期。地区差异上，山区较平原区降水变化幅度更大，但周期平稳，突变时间更早。

The annual precipitation time series of 20 climate stations in the northern part of Haihe River Basin from 1956 to 2012 were analyzed in this paper. The spatial and multi-temporal characteristics of the rainfall were analyzed from the aspects of trend test, period analysis, breakpoint detection and spatial heterogeneity analysis. The results showed that: (1) the rainfall of the northern part of Haihe River Basin decreased by 14.9mm per ten years; (2) rainfall of different time scales had significantly different characters: the monthly rainfall was steady, with rainfall in October and November decreasing significantly and that in May and June increasing significantly; the rainfall in spring and autumn were relatively stable and the decline in summer and winter were of significance; the annual rainfall were of 28 years period and switched from wet season to dry season in around 1980s. (3) annual rainfall in mountain areas reduced at a rate twice as quick as that in plain areas, but had more solid period and earlier breakpoint.

国家自然科学基金项目(51309249，51379216)；水利部公益行业科研专项（201401041）；国家重点基础研究发展计划（2010CB951100）；“十二五”国家科技支撑计划资助项目（2012BAC19B03）