皇甫川流域1955-2013年水沙变化趋势与周期特征

为揭示黄河流域重要的产沙支流皇甫川在新时期水沙如何变化,采用Mann-Kendall检验、Pettitt检验及Morlet小波变换,分析了皇甫川流域1955-2013年水沙变化的趋势、突变和周期变化特征.结果表明:在99％显著性水平下,皇甫川流域的年径流量和输沙量均呈显著减少趋势,且径流量的减少大于输沙量的减少,进入21世纪以来,水沙年际变异更为显著;径流量、输沙量序列一级突变点均发生在1984年,二级突变点有所不同,年输沙量序列突变时间(2003年)晚于年径流量序列突变的时间(1998年);水沙演化过程中均存在4个尺度的周期变化,分别为22～32,13～21,7～12,3～6 a和23～32,13～22,7～12,3～6 a;在径流量和输沙量整体减少的趋势下,2011-2020年径流量将处于相对偏丰阶段,而输沙量在2013-2018年将处于相对偏多沙时期.研究表明,皇甫川流域径流量和输沙量的减少是气候的暖干化和渐强的人类活动综合作用的结果,而大规模的水土保持措施是水沙减少的重要影响因素.

Variation Tendency and Periodic Characteristics of Streamflow and Sediment Discharge in Huangfuchuan Watershed from 1955 to 2013

To reveal how streamflow and sediment discharge change in the new period of importance producing sediment of Huangfuchuan Watershed,the tributary of Yellow River.The Mann-Kendall test,Pettitt's test and wavelet transform were applied to detect the trends,abrupt changes and periodical variation of streamflow and sediment discharge from 1955 to 2013 in the Huangfuchuan Watershed.The results showed that significant reductions in both streamflow (Z=-5.01) and sediment discharge (Z=-4.55) were detected with a significance level of 99％,as well as the reduction of streamflow (β=-0.03) was greater than sediment discharge (β=-0.01).Especially in the 21st century,the interannual variability of streamflow and sediment discharge was more significant.The first abrupt change points of both annual streamflow and sediment discharge appeared in 1984,while the second abrupt change points of these were not in the same year,for sediment discharge in 2003 later than streamflow in 1998.The periodic variation of streamflow and sediment discharge had four scales,there were 22～32 years,13～21 years,7～12 years,3～6 years scales and 23～32 years,13 ～22 years,7～12 years,3～6 years scales.As the amounts of streamflow and sediment discharge reducing as a whole,the streamflow would be in the wet period in 2011-2020,while the sediment discharge would be in the high sediment in 2013-2018.The research results showed that the decrease in the streamflow and sediment discharge in Huangfuchuan Watershed was the result of the combination with warming and drying climate and intensive human activities.However,a series of large-scale soil and water conservation measures were the vital factors leading to significant reduction in streamflow and sediment discharge in Huangfuchuan Watershed.