Study On The Influence Of Climate Change On Runoff In Biliu River Basin

The Biliu River is the largest river in Dalian and plays an important regulatory role in the Biliu River water system.The impact of climate change on watershed hydrological processes has become a new research topic.The application of watershed hydrological modelling to simulate and predict the impact of climate change on runoff in river basins is of great theoretical and practical significance for flood control and drought prevention planning and long-term development and utilization of water resources in the Biliu River Basin.This study starts with the hydrological and meteorological data from 1978 to2005 in the Biliu River Basin from the impact of climate change on runoff in the basin.To avoid the uncertainty of the single analysis method,this paper has analyzed the Biliu River Basin for nearly 30 years using four methods.The temperature,relative humidity,sunshine hours,maximum and minimum temperatures,wind speed and humidity trends and their mutation characteristics.The meteorological factors that produce abrupt climate change and significant climate change in the study area are mainly the lowest temperature and the highest temperature.Therefore,this paper takes the Biliu River Basin as the research object,uses the temperature as the influencing factor of the SWAT model climate model,divides the basin into 145 hydrological response units,and thus simulates the runoff in the basin.The year-by-year of 28 years in the basin from 1978 to2005 The monthly runoff data was measured on a monthly basis and the sensitive parameter range of the watershed model was obtained.The SWAT model's runoff simulation results show that the SWAT model performs well in this basin.Both the Nash coefficient and R2 of measured runoff and simulated runoff exceed 0.85.The SWAT model can accurately perform the runoff changes in this area.Evaluation and analysis.In order to further determine the impact of climate change conditions on the hydrological conditions in the Biliuhe Reservoir Basin.This paper uses four climate models to compare simulated temperature and precipitation factors with measured values from 1978 to 2005,analyzes the accuracy of each model's simulation of temperature and precipitation,and simulates four models under the RCP4.5 scenario.The Future Climate Change in the Biliuhe Reservoir Basin from2040.The results show that:(1)The HIRHAM5 and the ICHEC-EC-EARTH models have the best overall predictions of the minimum and maximum temperatures,and the other three models have higher prediction accuracy,and the simulated correlation coefficients of the four models to the minimum and maximum temperatures.Both are at 0.88 and above to meet actual needs.(2)The simulation accuracy of daily rainfall in flood season by RegCM4,CCLM5-0-2and ICHEC-EC-EARTH models is higher than that in the whole year.The four models had higher simulated precision for the total precipitation,especially small deviations.Among them,the simulation accuracy of the total precipitation in the flood season by the RegCM4,CCLM5-0-2,and ICHEC-EC-EARTH models was higher than the annual average.In the later model study,the accuracy of different models for different time periods should be considered,and the advantages of different models should be explored,and multi-mode fusion should be carried out.(3)The simulation effect of Reg CM4 on heavy rain,heavy rain,and heavy rainstorm is better than other models.CCLM5-0-2 and MPI-M-MPI-ESM-LR models have the best simulated effect on moderate rain,and four models on light rain.The simulation results are all poor,showing too many simulations,and the total amount of deviation.(4)Enter the four modes of RCP4.5 scenarios to get the future climate scenarios of the basin.The results show that in the four modes,the future minimum temperature,maximum temperature,and precipitation all show an upward trend.(5)The correlation between runoff simulated values and measured values obtained by RegCM4 model is the best,especially for the simulation of monthly runoff,the correlation is 0.59,CCLM5-0-2 and MPI-M-MPI-ESM-LR model The precision of the runoff is high,especially for the forecast of total runoff volume,which is small enough to meet the actual situation.Therefore,according to the RegCM4 model,the trend of future runoff changes in the basin can be predicted,and the future trends of total runoff in the basin can be obtained based on the CCLM5-0-2 and MPI-M-MPI-ESM-LR models.(6)RegCM4 model shows that the total amount of future runoff in the river basin shows an increasing trend.In 2023 and 2030,the total runoff reaches the lowest value.According to CCLM5-0-2 and MPI-M-MPI-ESM-LR model,the basin will be divided into two periods 2006-2023 and 2024-2040 in 2006-2040,and the total annual simulated average runoff in two periods will be obtained.They were331.00 m~3/s and 344.13 m~3/s,respectively,and the simulated flood season average runoff volume was 169.69 m~3/s and 187.05 m~3/s,respectively.(7)Using these four climate model outputs as SWAT model input to perform runoff simulation has lower model coefficient,which indicates that the coupling of climate model and SWAT model is unsuccessful,the simulation effect of climate model needs to be further improved,and the meteorological observation data is still more current.Valid input data.