密云水库流域入库径流量变化特征及归因研究

The characteristics and attribution of runoff change in the Miyun reservoir watershed

运用累积距平法、小波分析和累积量斜率变化率比较法,对密云水库流域1960~2014年入库径流量时间序列进行研究。结果表明：1）密云水库流域入库径流量存在两个突变年份,即1979和1998年。2）1979年前流域径流量基本上呈增加趋势;1980~1998年,径流量呈先减后增的趋势;1999年后,径流量呈明显减少趋势。3）密云水库流域入库径流量序列存在7a和16a左右的震荡周期,持续时间分别为1960~2000年和1960~2014年。4）气候变化和人为活动对入库径流量影响具有阶段性特征：1979年以前,气候是影响径流量波动的主要因素;1980~1998年,气候因素是径流增加的原因之一,人为因素成为影响径流量减少的主要因素;1999年以后,人为活动仍是入库径流减少的主要原因;与1980~1998年相比,其对径流量减少的影响有所降低,气候变化对入库径流量减少的贡献率略有增加。

Based on the annual runoff data from 1960 to 2014 in Miyun reservoir watershed, the change trend, abrupt time, periodic oscillations and the contribution of climate change and human activities were researched using the methods of cumulative anomaly, wavelet analysis and slope change ratio of cumulative quantity. The main results were showed as follows： （1） There existed two abrupt point years in runoff： 1979 and 1998. （2） The trend of runoff series varied over past decades, which was increasing before 1979, decreasing at first then increasing between 1980 and 1998, dramatically decreasing from 1999 to 2014. （3） The main periodic oscillations （ 7 - year and 16 - year） existed in the annual runoff variation, which lasted from 1960 to 2000 and from 1960 to 2014,respectively. （4）The contribution of climate change and human activities varied during different study periods ： climate change was the key factor affecting runoff change before 1979, while the human activities （ 100. 26% ） became the major reason from 1980 to 1998. Although human activity was the first important cause, the climate factor including precipitation （ 12.45 % ） and potential evapotranspiration （ - 12.38 % ） had evolved to a important reason from 1999 to 2014.