基于DFA的无定河径流长期变化趋势及持续性研究

河川径流量的变化对水资源的开发利用和国民经济的发展具有很大的影响。采用K0lmogorov—Smimov检验方法对无定河流域两个主要水文站赵石窑站和白家川站逐月径流量序列进行正态性检验，在此基础上运用DFA分析方法，估算两站时间序列的研示度指数，预测该流域径流量的未来变化趋势及其持续性，并采用随机重排法对估算结果进行了稳定性检验。分析结果显示：赵石窑和自家川两站径流时间序列的a标度指数分别为0．52和0．56，均大于0．5，径流时间序列表现为较强的长程依赖性，表明无定河流域在过去近50a内径流量的总体上呈下降趋势，在未来一段时间内，还将持续一段时间。对原时间序列随机重排后，两站月径流序列的6α标度指数都变小，分别为0．48和0．49，接近于0．5，进一步证明原序列确实存在着标度不变性。研究结果对流域的水资源规划、管理与合理利用有帮助。

Long-term trends and sustainability analysis of runoff in the Wuding River basin

The changes of river runoff has a great influence on the exploitation and utilization of water resources as well as the development of national economy. Normality for the monthly series of runoff at two mainly hydrologic stations--Zhaoshiyao and Baijiaehuan in the Wuding River basin were test by the Kolmogorov--Smimov technique. DFA method was used to estimate the α scaling exponent and forecast future trends and persistence ofrunoffbased on the test. The reliability of this estimation was tested by comparing α values obtained from original time series and from stochastically reset ones. The results showed that： the separate test results for runoff at two stations are 0.52 and 0.56, both of the α values are above 0.5, α values for runoff time series showed long-range dependence, which indicates that during the past half century runoff decreased in the whole Wuding River basin and will continue to decrease in the future, α values of the two stations decrease to 0.48 and 0.49, both are about 0.5, after random rearrangement of the original runoff sequence, which further prove that the sequence does exist scale invariance. The result should be helpful for local water resources planning, intelligent use and management.