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The Research On Improving And Simulating Of Distributed Snowmelt Model Of Snow-seasonal Frozen Soil

Posted on:2016-09-23Degree:MasterType:Thesis
Country:ChinaCandidate:A X XiFull Text:PDF
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Seasonal frozen soil in arid areas as special soil, has become one of the indispensable factor of restricting the hydrology, agriculture, engineering, due to its freezing melting in spring in winter, the soil surface temperature and humidity have great changes, the melting snow infiltration process affect the reaction, thus affecting the snow melt runoff simulation the accuracy and precision of flood forecasting and warning. Freezing and thawing rule and the freezing and thawing process and build frozen soil water heat coupling module has certain necessity of seasonal frozen soil, technical support for the accurate simulation of river flow, and the people of the arid region hydrology information management of the safety of life and property have certain security role.This study firstly in freezing and thawing period Juntanghu basin on the northern slope of Tianshan Mountains permafrost data in seasonal frozen soil area of the observed field, temperature and humidity data including frozen soil depth and soil, effects of freezing and thawing and the variation characteristics of the process of freezing and thawing soil moisture and temperature in the seasonal frozen soil, and discusses the effect of soil moisture content distribution and heat transfer characteristics of snow melt runoff; according to the importance of permafrost frozen soil water and heat equation had been established based on the frozen soil module, parameter threshold, Juntanghu basined as the study area through observation and experiment, the freezing and thawing process to simulate snow and frozen soil and the whole basined snow melt runoff, the results showed that:(1)By 2013 and 2014, soil water content in each layer of different levels of soil moisture migration and depth of freezing and thawing of permafrost and snow melt water amount of infiltration. Especially the surface and soil temperature and soil moisture migration in 10 cm changed obviously, the regulation and control of flood has great influence, will have certain feedback effect on snowmelt runoff.(2)In 2014 the simulated soil water content and soil temperature and average relative errors were 5.573%, 6.813%, generally small, good simulation accuracy. In 2013 and 2014 test field grid scale snow melt runoff conduct simulation, in 2013 the simulation of the linear correlation coefficient was determined for R2=0.968 and R2=0896 in 2014.(3)Coupled snow melting module simulate the flow of the basin, and combining with the WRF weather forecast models and isochrones method had been used to simulate the runoff simulation,results show that: in 2014 the determination coefficient is 0.908, the relative error of the peak value was 10.709%. The maximum value of relative error of the peak value was 27% and the minimum value was 0.300%.The maximum value of the determination coefficient was 0.999 and the minimum value was 0.541. The results indicates that the surface soil moisture and temperature on the infiltration of melt water had a regulatory role, thus affecting the underlying surface runoff. Therefore, the establishment of frozen soil water heat module simulated snow melt runoff better, while so to utilization in permafrost region water resources and flood forecast is of great research significance.
Keywords/Search Tags:Seasonal frozen soil, frozen soil migration of heat and water, the distributed model of snow-seasonal frozen soil, Juntanghu Lake basin
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