The impacts of future climate change on streamflow of the Dongliao River Watershed located in Jilin Prov-ince, China have been evaluated quantitatively by using a general circulation model （HadCM3） coupled with the ...The impacts of future climate change on streamflow of the Dongliao River Watershed located in Jilin Prov-ince, China have been evaluated quantitatively by using a general circulation model （HadCM3） coupled with the Soil and Water Assessment Tool （SWAT） hydrological model. The model was calibrated and validated against the historical monitored data from 2005 to 2009. The streamflow was estimated by downscaling HadCM3 outputs to the daily mean temperature and precipitation series, derived for three 30-year time slices, 2020s, 2050s and 2080s. Results suggest that daily mean temperature increases with a changing rate of 0.435~C per decade, and precipitation decreases with a changing rate of 0.761 mm per decade. Compared with other seasons, the precipitation in summer shows significant downward trend, while a significant upward trend in autumn. The annual streamflow demonstrates a general down-ward trend with a decreasing rate of 0.405 m^3/s per decade. The streamflow shows significant downward and upward trends in summer and in autumn, respectively. The decreasing rate of streamflow in summer reaches 1.97 m^3/s per decade, which contributes primarily to the decrease of streamflow. The results of this work would be of great benifit to the design of economic and social development planning in the study area.展开更多
As an important tool for the description and analysis of hydrological processes,the watershed hydrological model has been increasingly applied to watershed hydrological simulations and water resource management.Howeve...As an important tool for the description and analysis of hydrological processes,the watershed hydrological model has been increasingly applied to watershed hydrological simulations and water resource management.However,in most cases,model parameters are only determined in a calibration scheme which fits the modeled data to observations,thus significant uncertainties exist in the model parameters.How to quantitatively evaluate the uncertainties in model parameters and the resulting uncertainty impacts on model simulations has always been a question which has attracted much attention.In this study,two methods based on the bootstrap method(specifically,the model-based bootstrap and block bootstrap)are used to analyze the parameter uncertainties in the case of the SWAT(Soil and Water Assessment Tool)model applied to a hydrological simulation of the Dongliao River Watershed.Then,the uncertainty ranges of five sensitivity parameters are obtained.The calculated variation coefficients and the variable parameter contributions show that,among the five parameters,ESCO and CN2 have relatively high uncertainties:the variation coefficients and contribution rates are 23.98 and 70%,14.43 and 18%,respectively.The three remaining parameters have relatively low uncertainties.We compare the two uncertainty ranges of parameters acquired by the two bootstrap methods,and find that the uncertainty ranges of parameters acquired by the block bootstrap are narrower than those acquired by the model-based bootstrap.Further analysis of the effects of parameter uncertainties on the model simulation reveals that the parameter uncertainties have great impacts on results of the model simulation,and in the model calibration stage 60%70%of runoff observations were within the corresponding 95%confidence interval.The uncertainty in the model simulation during the flood season(i.e.the wet period)is relatively higher than that during the dry season.展开更多
基金Under the auspices of Major Science and Technology Program for Water Pollution Control and Treatment(No.2009ZX07526-006-04-01)
文摘The impacts of future climate change on streamflow of the Dongliao River Watershed located in Jilin Prov-ince, China have been evaluated quantitatively by using a general circulation model （HadCM3） coupled with the Soil and Water Assessment Tool （SWAT） hydrological model. The model was calibrated and validated against the historical monitored data from 2005 to 2009. The streamflow was estimated by downscaling HadCM3 outputs to the daily mean temperature and precipitation series, derived for three 30-year time slices, 2020s, 2050s and 2080s. Results suggest that daily mean temperature increases with a changing rate of 0.435~C per decade, and precipitation decreases with a changing rate of 0.761 mm per decade. Compared with other seasons, the precipitation in summer shows significant downward trend, while a significant upward trend in autumn. The annual streamflow demonstrates a general down-ward trend with a decreasing rate of 0.405 m^3/s per decade. The streamflow shows significant downward and upward trends in summer and in autumn, respectively. The decreasing rate of streamflow in summer reaches 1.97 m^3/s per decade, which contributes primarily to the decrease of streamflow. The results of this work would be of great benifit to the design of economic and social development planning in the study area.
基金supported by the Major Science and Technology Program for Water Pollution and Treatment of China(Grant No.2012ZX07201-001)
文摘As an important tool for the description and analysis of hydrological processes,the watershed hydrological model has been increasingly applied to watershed hydrological simulations and water resource management.However,in most cases,model parameters are only determined in a calibration scheme which fits the modeled data to observations,thus significant uncertainties exist in the model parameters.How to quantitatively evaluate the uncertainties in model parameters and the resulting uncertainty impacts on model simulations has always been a question which has attracted much attention.In this study,two methods based on the bootstrap method(specifically,the model-based bootstrap and block bootstrap)are used to analyze the parameter uncertainties in the case of the SWAT(Soil and Water Assessment Tool)model applied to a hydrological simulation of the Dongliao River Watershed.Then,the uncertainty ranges of five sensitivity parameters are obtained.The calculated variation coefficients and the variable parameter contributions show that,among the five parameters,ESCO and CN2 have relatively high uncertainties:the variation coefficients and contribution rates are 23.98 and 70%,14.43 and 18%,respectively.The three remaining parameters have relatively low uncertainties.We compare the two uncertainty ranges of parameters acquired by the two bootstrap methods,and find that the uncertainty ranges of parameters acquired by the block bootstrap are narrower than those acquired by the model-based bootstrap.Further analysis of the effects of parameter uncertainties on the model simulation reveals that the parameter uncertainties have great impacts on results of the model simulation,and in the model calibration stage 60%70%of runoff observations were within the corresponding 95%confidence interval.The uncertainty in the model simulation during the flood season(i.e.the wet period)is relatively higher than that during the dry season.
