| The Xilin River is a typical steppe inland river in China.The Xilin Gol grassland in the basin is a typical grassland in the cold and arid region.It is a year-round drought and rare precipitation is the main climatic feature of the region.The distribution of precipitation during the year is seasonal,and the precipitation in winter accounts for a large proportion of the annual precipitation.The seasonal snow formed by snowfall is an important freshwater resource in the region.The snow melt in spring is regional groundwater.One of the main sources of surface water supply,but snowfall can also cause natural disasters such as snow disasters and snowmelt floods in spring grasslands,threatening the lives and property of people in grassland pastoral areas,affecting the development of local agriculture and animal husbandry and ecological civilization.Therefore,accurately identify the amount of snowfall in winter,understand the trend of snowfall change,grasp the temporal and spatial variation of concentration and concentration period,simulate and predict the evolution trend of snowmelt runoff under future climatic conditions,and plan for water resources planning and natural disaster prevention in Xilin River Basin.Economic development is of great significance.Based on the dual temperature threshold method combined with the statistical index equation probability estimation to identify the snowfall in the study area,and obtain more accurate snowfall data,wavelet analysis,mutation test,R/S analysis and other methods are used to analyze the concentration period of snowfall in the basin.Concentration change characteristics,and predict the future snowfall law.Using the water temperature data from 2014 to 2016 combined with remote sensing data(snow area),the adaptability study of the SRM snowmelt runoff model in the Xilin River Basin was studied and the evolution of snowmelt runoff under future climate change was predicted.The main results of the paper are as follows:(1)The snowfall identification method combined with the double temperature threshold method and the snowfall recognition equation can better estimate the snowfall at each station in the Xilin River Basin,and the correlation coefficient is above 0.89 with an error of less than 4%;1980-2016 tin The estimated snowfall changes among the sites in the Linhe River Basin are inconsistent,and the snowfall in the whole basin shows a trend of increasing eastward and decreasing westward.According to the results of mutation detection,the typical sudden change point of the basin is taken in 1980,and the simulation scheme of temperature and precipitation change is established.It is concluded that the increase in temperature contributes negatively to the change in snowfall during the snowfall period.The increase in precipitation contributes positively to snowfall.The combination of temperature and precipitation will promote the increase of snowfall.(2)The snowfall at Xilinhot Station in the basin is relatively concentrated,while the snowfall at Abaqi Banner is the least concentrated.The southern part of the basin is more concentrated in the south than in the north,and the trend of increasing or decreasing concentration is decreasing in the west and increasing in the east.Most of the sites in the basin have a common concentration period in early December,and the concentration period is more in the early years.Concentration has a cyclical change of about 25a.During this period,snowfall will undergo alternating-concentration-concentration alternating changes.The concentration period changes with 24a as the main cycle,and there is early-late-early alternation in the main cycle.Changes,and the concentration period after 2016 is still in the early stages.The concentration of stations in the basin will show an anti-sustainability in the future.(3)The SRM model can better reflect the trend of runoff during the snowmelt period of the Xilin River,and effectively capture the arrival date and peak flow of the snowmelt runoff.The goodness of fit of the simulated values determines the coefficient(R2)and the volume difference(Dv),which are superior to the model simulation accuracy mean published by the World Meteorological Organization.The model performs better in the Xilin River Basin.In the future,the peak flow of snowmelt runoff will increase with the increase of precipitation.The time of runoff flow will increase with the increase of temperature.The total amount of snow runoff will show that the runoff will increase with the increase of temperature,also when the precipitation increases.Runoff will also increase.Precipitation will be the dominant cause of future snowmelt runoff changes. |
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