Distributed Simulation And Evolution Law Of Water Cycle In The Daqing River Basin

As a condition for human survival and an important material basis for national economic development,water resources have gradually become the focus of attention at home and abroad.Climate change and the intensification of human activities not only have a huge impact on water resources,but also will inevitably cause changes in the water cycle system.As a result,it will accelerate the deterioration of water resources and hinder the development of economic and social in most countries.Therefore,it is urgently needed to develop sustainably and manage for the existing water resources,and the premise of this work is to grasp the influence of Hydrometeorology and other factors on the evolution of water resources cycle.Climate change causes changes in water cycle elements such as temperature,precipitation,and runoff in time and space,resulting in more serious water resources problems,and the future contradiction between supply and demand in the river basin will become more prominent.With global warming and the gradual increase in water demand in the watershed,it is particularly urgent and important to fully understand and analyze the evolution law of the water cycle in the watershed under climate change.This article first uses modern statistical methods to analyze the evolution characteristics of the basin's water cycle,and the evolution of the climatic factors affecting the water cycle in the Daqing River Basin.On this basis,according to DEM data,measured river network data,soil data,and long series of hydrometeorological data,a distributed hydrological model of the Daqing River Basin is established to simulate the hydrological cycle system of the Daqing River Basin.Meanwhile,the statistical downscaling model is used to perform downscaling simulation and predict the climate elements in the global climate model,and the meteorological data will be inputted to the distributed hydrological model,so as to obtain the runoff prediction data of the Daqing River Basin under different climate scenarios.The result can better analyze the impact of climate change on water resources,and provide references and basis for the rational development and utilization of water resources in the Daqing River Basin.The conclusions are as follows.(1)The hydrometeorological elements of the Daqing River Basin from 1958 to 2017 was studied by using various statistical analysis methods.The results show that:(1)from the perspective of spatial distribution,there are spatial imbalances in the annual average temperature and precipitation;(2)there are homogeneity in the time series of temperature,precipitation and runoff at 95% confidence level;(3)the annual average temperature of the river basin is significant.The rising trend,precipitation and runoff change trend is not significant;(4)the annual average temperature of the basin has obvious mutation,while runoff and precipitation have no significant mutation;(5)the temperature,precipitation and runoff elements in different periods have multiple characteristic time scales,with different periodic components,and the periodic change characteristics of runoff and the periodic change characteristics of temperature and precipitation.(2)According to the long series of measured hydrological data of Daqing River Basin,based on ArcGIS software,through the steps of DEM data processing,water flow direction extraction,concentration accumulation calculation,river classification,river network extraction,sub basin division and sub basin coding,a distributed hydrological model suitable for Daqing River Basin is established,and the parameter calibration and verification are completed.The results show that the Hebei model has a good applicability in the Daqing River Basin,and can be applied to practical problems.(3)Based on the statistical downscaling model SDSM,the downscaling model of temperature and precipitation elements in Daqing River Basin is established,and the simulation ability evaluation of model calibration and validation period is completed.The results show that the simulation results of the model are relatively reliable,which can be applied to the prediction of the future change trend of climate elements such as temperature and precipitation in Daqing River Basin under CMIP5 mode.(4)The temperature and precipitation data of 2020-2100 under three climate scenarios obtained from downscaling analysis are input into Hebei model to predict the runoff process of Daqing River Basin in the next 80 years.In general,the future runoff under RCP 2.6 scenario shows a downward trend,while the future runoff under RCP 4.5 and RCP 8.5 scenarios shows an upward trend,and the increase of RCP 8.5 scenario is larger than that of RCP 4.5 scenario.