Study On The Interaction Between Precipitation And Land Cover In Huang-huai-hai River Basin

Taking the Huang-Huai-Hai River Basin as the study area,this study investigates the interaction mechanism between various water cycle processes(precipitation,water production,etc.)and land use/land cover change in recent decades.Firstly,the spatiotemporal variation characteristics of NDVI,NPP,land use and precipitation are analyzed.Then,the spatial correlation method is used to quantitatively analyze the responses of NDVI and NPP to precipitation changes.And spatial distribution data of NDVI and NPP in 2025 are predicted based on Spatio-Temporal Regression Ordinary Kriging.Finally,the impact of land use change on regional water yield is quantitatively analyzed based on InVEST model.And regional water yield data in 2025 is predicted based on Spatio-Temporal Ordinary Kriging and CA-Markov models.This study reveals the interaction between water and soil resources in the Huang-Huai-Hai River Basin on a macro scale,and provides a scientific reference for the realization of comprehensive management of the watershed,the adjustment of soil and water loss and conservation,the optimization of regional water and soil resources structure,the rational allocation of water and soil resources and the improvement of soil and water ecological environment.The main known research results in this paper are as listed below:(1)In recent decades,land use changes in the Huang-Huai-Hai River Basin are dominated by cultivated land and construction land.And the changes of NDVI,NPP and precipitation mainly show an increasing trend.(2)In the past ten years,there have been positive correlations between NDVI,NPP with precipitation in most areas of the Huang-Huai-Hai River Basin.In terms of the year,the relationships between NDVI,NPP with precipitation in the three seasons of spring,summer,and autumn are mostly positively correlated,while winter is mostly negatively correlated.In terms of hysteresis,NDVI and NPP have the greatest response to precipitation in the same period in spring.And NDVI and NPP have a one-month lag in response to precipitation changes in summer and autumn.NDVI and NPP have a two-month lag in response to precipitation changes in winter.The forecast results show that the NDVI and NPP values of the Huang-Huai-Hai River Basin in 2025 will both increase compared to 2010.(3)From 1980 to 2010,the water yield depth in most areas of the Huang-Huai-Hai River Basin increases first,then decreases,and then increases,and finally shows an overall increase.Combined with the changes in land use type,it is found that the change of land type water yield depth is positively proportional to the change of cultivated land and grassland area,inversely proportional to the change of forest land,waters and construction land area,and has no obvious relationship with the change of unused land area.Through the prediction of the water yield depth of the basin in 2025,it is found that the average water yield depth of the basin in 2025 is lower than that in 2010.(4)Based on the comprehensive analysis of the interaction results of soil and water resources,it is found that the change of climate precipitation will lead to the change of NDVI\NPP,which represents that the growth of natural vegetation and crops on the surface is affected.And then it causes the change of phenological period and the change of water demand.This will lead to changes in the composition and scale of land use and ecological pattern such as woodland and grassland on the surface,thus affecting surface water resources and water cycle.Finally,the impact is returned to precipitation.In other words,water resources and land resources are interactive and coupled,influencing and dependent on each other.