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极端降水事件是导致黄土高原水土流失的主要原因之一,分析其变化趋势可为该区的生态建设提供重要的参考信息。选取泾河流域为研究区域,基于Mann-Kendall和小波分析等方法,分析了1965年-2005年极端降水事件的降水量、降水天数、降水强度和严重干旱次数等的变化趋势、突变、年代际变化和振荡周期等。结果表明,泾河流域极端降水事件的整体变化趋势不显著,但其发生频率和强度等都可能呈上升趋势,且存在空间差异,流域中下游呈上升趋势而流域西南部和北部呈下降趋势。各指标均呈波动变化,但基本都在1985年以后呈上升趋势,且在2000年左右发生多次上升突变;波动周期为2～3a,7～8a,13a和17a。尽管变化趋势不显著,但极端降水事件的各指标都趋于升高,表明未来极端降水事件可能对泾河流域的水土保持工作造成更加严重的威胁。
The extreme precipitation event is one of the main causes of soil erosion in the Loess Plateau. Analyzing the changing trend can provide important reference information for the ecological construction in this area. Based on the Mann-Kendall and wavelet analysis methods, this paper analyzed the trend of precipitation, precipitation days, precipitation intensity and severe drought frequency in extreme precipitation events from 1965 to 2005. The variation, decadal, Change and oscillation period and so on. The results show that the overall trend of extreme precipitation events in Jinghe River Basin is not significant, but its occurrence frequency and intensity may be upward trend, and there are spatial differences. The middle and lower reaches of the basin are on the rise and the southwest and north of the basin are on the downward trend. All the indexes fluctuated, but all basically increased after 1985, and many rising and abrupt changes took place around 2000; the fluctuation period was 2 ~ 3a, 7 ~ 8a, 13a and 17a. Although the trend of change is not significant, the indicators of extreme precipitation events tend to rise, indicating that the future extreme precipitation events may pose a more serious threat to soil and water conservation in the Jinghe River Basin.