大渡河流域年径流变化特征及其归因分析

根据1951—2012年大渡河流域内气象站年降水量、年平均气温和铜街子站年径流量资料，利用Mann-Kendall秩次相关检验法识别年径流量变化趋势，基于小波分析法检验其周期成分，采用有序聚类法、累积距平法及Pettitt法诊断年径流量突变点，利用累积量斜率变化率比较法揭示气候变化与人类活动对流域年径流量的影响程度。研究结果表明:1951—2012年大渡河流域年径流量整体呈不显著的减少趋势，其中，1951—1968和1988—2012年期间呈不显著的减少趋势，1969—1987年期间呈不显著的增加趋势；年径流量存在7年、11年、17年和28年的周期成分；流域年径流量在1968年和1987年发生突变；以1951—1968年为基准期，1969—1987年期间气候变化和人类活动对大渡河流域径流量减少的贡献率分别为36.22%和63.78%；在1988—2012年期间的贡献率分别为33.68%和66.32%；人类活动是大渡河流域年径流量变化减小的主导因素，气候变化是次要因素。

Variation characteristics of annual runoff and its attribution analysis in Dadu River basin

According to the data of annual precipitation, annual average temperature of climatological stations and annual runoff of Tongjiezi Station in the Dadu River basin from 1951 to 2012, the Mann Kendall rank correlation test was used to identify the trend of annual runoff sequence, the periodic component was tested based on the wavelet analysis method, the sequential clustering method, the cumulative anomaly method and the Pettitt method were used to diagnose the change point, and the effect of climate changes and human activities on the annual runoff of the basin was revealed based on the comparison of the slope change rate of the cumulative amount. The results show that in the past 60 years, during 1951—1968, the annual runoff showed an insignificant decrease trend, the period of 1969—1987 showed an insignificant increase trend, the period of 1988—2012 showed an insignificant decrease trend, and the period of 1951—2012 showed an insignificant decrease trend; there were 7, 11, 17 and 28 years cycle components; in the past 60 years, change points of the annual runoff in the Dadu River basin were in 1968 and 1987; using 1951—1968 as the base period, during 1969—1987, the contribution rate of climate change and human beings activities to the reduction of annual runoff in the Dadu River basin was 36.22% and 63.78% respectively; during 1988—2012, the contribution rate of climate change and human activities to the reduction of annual runoff was 33.68% and 66.32% respectively; and in sum, human activities are the main factor and climate change is the secondary factor.