气候变化和人类活动对鄱阳湖流域径流过程影响的定量分析

Quantitative analysis the influences of climate change and human activities on hydrological processes in Poyang Basin

量化气候变化和人类活动对流域水文影响及其对流域水资源规划和管理具有重要的理论与现实意义.采用水文模型和多元回归法定量分析气候变化和人类活动对鄱阳湖'五河'径流的影响,并通过与灵敏度分析法对比来进一步验证分析结果 .研究表明,1970-2009年,气候变化和人类活动对鄱阳湖流域径流增加的贡献率分别为73%和27%.气候变化是饶河、信江和赣江径流增加的主导因素,而人类活动是修水径流增加的主要因素,是抚河径流减少的主要原因.另外,不同季节影响径流变化的主导因素又有不同,人类活动为干季(11月到次年2月)径流增加和湿季(4-6月)径流减小的主导因素,其贡献率分别为78.9%和82.7%.本研究可为鄱阳湖流域防洪抗旱及水资源优化配置提供重要科学依据.

The streamflow processes of the Poyang Basin are significantly altered due to combined influences from climate changes and human activities,which further triggers higher occurrence frequency of floods and droughts and hence serious water resources problems. In this sense,quantitative evaluations of influences from human activities and climate changes respectively are of greatly theoretical and practical merits in terms of planning and management of water resources. In this study,hydrological models and multivariate regression technique are used to identify quantitatively impacts of climate changes and human activities on streamflow variations of five tributaries of the Poyang Basin. Furthermore,the results are further corroborated by comparisons between the analyses by hydrological models and multivariate regression methods and also sensitivity analysis technique. The explained variables of the multivariate models are done using the adjustment coefficients with different explained variables,showing that the multiple regression models are the right ones with evaporation and the precipitation of the last month. The NASH coefficient for the AWBM model is larger than 0. 842,being better than the modeling results by the multivariate regression models. Meanwhile the impacts modeled by the above-mentioned techniques are similar,and are good for identification of the impacts of human activities and climate changes on streamflow variations. It should be noted here that the sensitivity method cannot exclude the base-period human influences. Due to increase of streamflow as a result of human interferences,the influence component by climate changes is usually exaggerated. Analysis of this study indicates that precipitation,potential evaporation and also human activities have the potential to increase the streamflow of the Poyang Basin and the fractional contribution is 27% and 73%,respectively. Climate changes can increase the streamflow of these five rivers considered in this study. Human activities increase the streamflow of the rivers except Fu River basin. In the Fu River basin,the streamflow decreases due to massive agricultural irrigation. Different influences can be identified for climate changes and human activities on tributaries of the Poyang Basin. Climate change is the major driving factor for the increase of the streamflow within the Rao,Xin and Gan River basins; however,human activity is the principle driving factor behind the increase of the streamflow of the Xiu River basin and also the decrease of the streamflow of Fu River basin. Meanwhile,different impacts of human activities and climate changes on streamflow variations are distinctly different on various temporal scales. On the annual time scale,increase of streamflow is large due to climate changes and human activities during 1970s- 1990 s and decrease of streamflow during 2000 s. On the seasonal scale,human activities can well increase streamflow during dry season（December to February of the subsequent year） and decrease streamflow during wet season（April to June） with the fractional contribution of 78. 9% and 82. 7% respectively. On the monthly scale,different influences of climate changes and human activities can be detected. Climate change is the main factor for the decrease of streamflow during May to June and human activities for the decrease of streamflow during February to May. The results of this study can provide theoretical ground for basin-scale water resources management under the influences of climate changes and human activities.