论文部分内容阅读
径流可再生性的变化是水循环研究中的重要科学问题,对于干旱、半干旱气候区水资源的可持续利用有重要意义。以黄河中游河口镇至龙门区间1950—2008年间的水文、气象资料以及人类活动(如引水、水土保持)等资料为基础,运用统计方法研究了径流可再生性指标Irr的变化及其成因。在59 a的时间尺度上,Irr在总体上具有明显的减小趋势,但具有次一级的波动,其变化可以分为4个阶段。研究发现,3个气候变量(年降水量Pm、年均气温Tm和夏季风强度指标SMI)与当年Irr的相关程度均不高,但它们的滞后作用对于Irr的影响十分明显,表明气候因子对于径流可再生性影响具有某种时间尺度效应。以Irr与某一气候因子的N年滑动平均值的相关系数与N的关系曲线的峰值或拐点所对应的N值作为气候因子影响Irr的特征时间尺度,确定了Pm、SMI和Tm影响径流可再生性的特征时间尺度分别为11、9和4 a。Irr与各项水土保持措施的面积及水土保持措施总面积之间均表现出显著的负相关。1998年以后开展的以大规模退耕还林(草)为中心的生态环境建设使得径流可再生性指标进一步降低。建立了Irr与气候暖干化指标和水土保持总面积之间的回归方程式,该方程表明,Irr随气候暖干化程度的增加而减小,随水土保持措施面积的增大而减小。
The change of runoff reproducibility is an important scientific issue in the study of water cycle and is of great significance to the sustainable use of water resources in arid and semi-arid climatic zones. Based on the hydrological and meteorological data and the human activities (such as water diversion and soil and water conservation) during the period 1950-2008 from Hekouzhen to Longmen in the middle reaches of the Yellow River, statistical analysis was conducted on the changes and their causes of the Irr indicators of runoff reproducibility. On the time scale of 59 a, Irr shows a clear trend of decreasing overall, but with sub-level fluctuations, the change can be divided into four stages. The study found that the correlation between the three climate variables (annual precipitation Pm, annual mean temperature Tm and summer monsoon intensity index SMI) and current year Irr are not high, but their hysteresis effect on Irr is very obvious, indicating that climate factors for Runoff reproducibility has some time scale effect. The effects of Pm, SMI and Tm on runoff can be determined by taking the peak value of N or the N value corresponding to the inflection point as the climatic factor to influence the characteristic time scale of Irr, taking Irr and N year moving average of a climatic factor as the correlation coefficient. The time scales of regenerative characteristics are 11, 9 and 4 a, respectively. There was a significant negative correlation between Irr and the area of water and soil conservation measures and the total area of soil and water conservation measures. The construction of ecological environment centered on large-scale conversion of farmland to forests (grass) since 1998 has further reduced the index of runoff renewables. The regression equation between Irr and climate warming index and the total area of soil and water conservation was established. The equation shows that Irr decreases with the increase of climate warming degree and decreases with the increase of soil and water conservation area.