Analysis Of Water Resources System Evolution And Carrying Capacity In Climate Change Of The Upper Basin Of The Hanjiang River

Under the influence of climate change and human activities,huge changes have taken place in the hydrological and water cycle process of the river basin,and problems such as water shortage and water disasters in some river basins have occurred frequently.There is an urgent need to carry out research on the carrying capacity of water resources in a river basin under climate change,which is of great guiding significance for the sustainable development of the river basin.Taking the upper basin of the Han River as an example,this paper systematically analyzes the evolution trend of water resources in the watershed,analyzes the future response of the water resources system of the watershed through the coupling of the global climate model and the SWAT model,and establishes a water resources system based on information entropy and gray system theory Based on the discriminant model of evolution direction,a calculation model for the dynamic carrying capacity of the watershed water resources system under climate change is proposed,and the early warning level of carrying capacity is divided according to the overload degree of the water resources carrying capacity.The main results and conclusions of this article are as follows:(1)Analyze the response of the basin's water resources system under future climate change scenariosA full analysis of the spatial and temporal evolution of water resources in the base period of the basin was carried out,taking into account future climate scenario changes,and using statistical downscaling methods to analyze the future response of the water resources system.The results showed that the falling water in the RCP4.5 and RCP8.5 climate scenarios was lower than the baseline The period increases slowly,the increase is not large,but the temperature has a clear increase trend compared with the reference period,the average rate of temperature increase reaches 0.03 ? / a.By constructing the SWAT model on the upper Han River,the meteorological factors under the two future climate scenarios are used as model-driven data sources to predict the future runoff change trend of the river basin.The results show that in 2021-2050 under RCP4.5 and RCP8.5 The runoff has increased from the baseline period,but it shows an increasing trend with time under the RCP4.5 scenario,and shows a decreasing trend with time under the RCP8.5 scenario.(2)Establish a discriminant model of the evolution direction of the water resources systemConsidering the impact of climate change on economic and social water demand and water availability,the water resources availability and water demand of each administrative region under the two future climate scenarios of RCP4.5 and RCP8.5 are calculated,and the water resources system is regarded as The grey system takes the water supply and water demand of the water resources system of the river basin as order parameters,and establishes the discriminant model of the evolution direction of the water resources system in combination with the information entropy theory.The results show that under the RCP4.5 and RCP8.5 scenarios,the entropy of the water resources system The value change is very small,that is,the state of the water resource system does not change significantly,and is basically consistent with the state of the initial water resource system.(3)Propose the carrying capacity model and early warning level of water resources system under climate changeDefine the dynamic carrying capacity of the watershed water resources system,establish a calculation model of the dynamic carrying capacity of the watershed water resources system under climate change,and use the overload of the water resources as the early warning indicator of the carrying capacity.The scenario is significantly higher than the RCP8.5 scenario.The water resources system in the river basin was overloaded in 20% of the years under the RCP4.5 scenario,while RCP8.5 was not overloaded.According to the criteria for classification of early warning levels,five early warnings within the watershed range occurred in the RCP4.5 scenario;no early warnings in the watershed range occurred under the RCP8.5 scenario,but multiple early warnings of blue and above occurred in the future scenarios of Shiyan District and Ankang District.In summary,the discriminant model of water resource system evolution direction and the early warning method of carrying capacity established under the climate change in this paper can well reflect the changing state of water resource system under different climate scenarios,and the adaptive regulation and extreme of future water resource system.Timely warning of climatic conditions provides a reliable basis.