The Applicability Of Multi-source Data In High Cold Alpine Areas Runoff Simulation And Impact On Yield Convergence Of LUCC Change

Due to its special geographical location and topography of the cold high Alpine areas, the number of the basin monitoring stations is very small and unevenly distributed, which means the measured data is not representative enough. for researching the hydrology rule reasonably of Alpine areas for the lacking of research data, to improve the accuracy of snowmelt runoff simulation, and have a better understanding and characterization of hydrology rule in cold Regions, the paper based on the drainage basin of kashi river of west tianshan mountain region as study area, the characteristics laws of CFSR(Climate Forecast System Reanalysis) reanalysis precipitation data were researched and analyzed; constructed distributed hydrological model of SWAT(Soil and Water Assessment Tool) model that suitable for middle and large basins and explored the effects of CFSR precipitation data on drainage basin simulation runoff; With different spatial resolution DEM data, analyzed the differences and its impact on runoff process; simulated runoff condition of the study area with the land use scenarios predicted by CA-Markov model, at the same time according to the actual situation, assuming two scenarios of landuse, simulated runoff condition of the study area with the land use scenarios assumed.Through the comparison of the CFSR precipitation data and measured precipitation data of rainfall, we find the relative error is 22.86%, to make the precipitation patterns consistent with the actual precipitation in the study area, modified CFSR precipitation data combining with the measured precipitation, and constructed the SWAT model, simulated the runoff process with the CFSR precipitation data before and after correction as model-driven data, we found that the simulated runoff variation trends of modified precipitation data was substantially consistent with the measured runoff data. The relative error between average and measured runoff monthly calibration period before and after modified of CFSR precipitation is 48% and 6%; relative error of validation period is 36% and 10%.Discussed the difference of the DEM resolution and influence on runoff process of its size with different spatial resolution of DEM data,And we find that as the DEM Resolution decreased, topography tends to be flat, which makes extraction of total watershed area, elevation range and maximum slope decrease. Due to the relief of the terrain, the decrease of the slope has a direct impact on the runoff yield and runoff process, which makes the runoff peak value less than the actual peak value, and the simulation result is not good.Land use/cover change(LUCC) will have certain effects on the regional underlaying surface area, thus changes the law of drainage basin hydrological processes?runoff and convergence production. Predicted the change conditions of LUCC data in 2020 of study drainage basin based on CA-Markov model, input the predicted date for the model which has been constructed and calibrated, contrast the simulation runoff and the situation of LUCC in 1990, found that the annual average runoff has changed only 0.49 m3/s over 30 years. According to constructed of two different LUCC scenarios, analyze the effects of LUCC change on hydrological processes, we can conclude that a substantial increase in the analog grass and made the simulation runoff decrease, and the elevation of study drainage basin above 3500 m increase great amount of snow and ice water resources, made the simulation runoff increased.