Simulation Of Ecosystem Water Yield And Analysis Of Influencing Factors In Typical Watershed Of The Qinghai Tibet Plateau

Water resources,as an important component of ecosystems,are essential natural resources for human activities and economic and social development,and provide basic guarantees for human survival.The protection and rational utilization of water resources are the foundation for ensuring human production and life.Visualizing the spatiotemporal changes in watershed water production and analyzing the main factors affecting water resource production are direct and effective methods for rational utilization of water resources and effective response to water resource shortages.Simulating water production is of great significance for maintaining human survival and water environment security.This article localizes and corrects the parameters of the water production model to improve the accuracy of the water production simulation results,and provides a reference for the evaluation of water production services in the ecosystem of the Qinghai Tibet Plateau.This article also evaluates the influencing factors of spatial differentiation characteristics of water production,compares and analyzes the similarities and differences of influencing factors between the Qinghai Lake basin and the source area of the Yellow River,in order to explore the current situation of water production and the changes in hydrological characteristics of the two basins,and provide scientific basis for protecting regional ecosystems.As a natural unit for the formation and transportation of surface water and groundwater,the changes in water yield and water conservation capacity of a basin have a significant impact on the water cycle process of the basin.This article focuses on the study of water yield in typical basins of the Qinghai Tibet Plateau.The Qinghai Tibet Plateau has a wide area and a complex and diverse ecosystem,with a large area of outflow areas and internal watersheds.Therefore,selecting typical watersheds for research can help analyze the factors affecting water yield.As a typical representative of the inner basin,the Qinghai Lake Basin is an important ecological security barrier in the northeast of the Qinghai Tibet Plateau,and its water resource management and protection are particularly important.The Yellow River source area,as a representative of the outflow area,is the main water source of the Yellow River Basin.Its water production changes directly affect the ecological security of the entire Yellow River Basin and the production and life of residents in the basin.The Qinghai Lake basin and the Yellow River source area are both important ecologically fragile and sensitive areas in the northeastern region of the Qinghai Tibet Plateau.Human interference,climate change,and environmental issues have all had a negative impact on the water production of the basin.Therefore,there is an urgent need for effective means to simulate and characterize the eco hydrological process in the Qinghai Lake basin and the source area of the Yellow River,evaluate their water yield,and analyze their spatial heterogeneity.Based on this,this study takes the Qinghai Lake basin and the source area of the Yellow River as the study area.Based on the land use of the eight periods from 1985 to 2020,combined with terrain,soil and meteorological data,the localized modified InVEST model and geographical detector method are used to simulate the water yield of the basin,evaluate the spatial differentiation characteristics of water yield,and analyze the attribution of its spatial heterogeneity.The main research conclusions are as follows:(1)During the research period,the trend of water production in both watersheds showed significant temporal changes.The variation range of water production in the Qinghai Lake Basin from 1985 to 2020 is 1.168 to 8.152 billion cubic meters,showing a trend of first decreasing and then increasing,and then decreasing and then increasing.The variation range of water production in the source area of the Yellow River from 1985 to 2020 is 15.208 to 30.244 billion m3,showing a trend of alternating decline and rise.(2)The spatial distribution of water production in the two watersheds during the research period has the same characteristics.The spatial distribution of water production depth in the Qinghai Lake Basin shows a high in the southeast and low in the northwest,with high value areas concentrated in Haiyan County.The interannual variation of water production depth shows an overall increasing trend.The water production depth in the source area of the Yellow River also shows a spatial distribution of high in the east and low in the west.The high value areas of water production depth are concentrated in Maqin County,Gande County,Jiuzhi County in the source area of the Yellow River,and Maqu County in the eastern Gannan Prefecture.The interannual variation of water production depth also shows an increasing trend.(3)The correlation between water yield and altitude in the two watersheds during the research period is different.On the vertical gradient of the Qinghai Lake Basin,there is a negative correlation between altitude and water yield,meaning that water yield weakens with the increase of altitude.The changes in land use types at different altitudes promote a decrease in water yield.In the source area of the Yellow River,there is a positive correlation between altitude and water yield on the vertical gradient.At low altitudes,the water yield remains relatively high.As the altitude increases,the proportion of land use types in the area continuously changes,and the water yield shows a trend of first increasing and then decreasing.(4)The results of geographical exploration show that there are significant differences in the explanatory power of each single factor to the spatial heterogeneity of water production.Precipitation and temperature are the main factors affecting water yield in the Qinghai Lake basin,the source area of the Yellow River,and different regions,with climate factors dominating the explanatory power in terms of categories.The explanatory power of various factors of landscape pattern index on the spatial distribution of water yield is relatively limited.The factor interaction detector reveals that the influence degree of spatial differentiation of water yield is determined by multiple factors.The two study areas as a whole are dominated by the interactive interpretation power of precipitation and actual evapotranspiration,followed by the interaction between climate factors and landform,soil type,and land use type factors,However,the combination of factors that interact at the county and altitude scales will exhibit differences based on the regional characteristics of each subregion.