Simulation Of Snowmelt Runoff In The Headwaters Of The Yellow River Using The UEB Model

The headwaters of the Yellow River is located in the north-eastern part of the Qinghai-Tibet Plateau,with low temperature and high altitude.In the past 60 years,temperature,precipitation and runoff in the Yellow River headwaters have changed greatly under global climate change,which affects the water conservation and ecosystem safety in the headwaters,as well as the economic and social development in the downstream.Therefore,it is of great practical significance to study the snowmelt runoff characteristics in the Yellow River headwaters,for better understanding of the evolution of hydrologic cycle and the change of water resources.In this paper,the Utah Energy Balance Snowmelt Model(UEB)was used to simulate rainfall and snowmelt runoff in the region of the Yellow River from the Yellow River Yen Hydrological Station to the Dari Hydrological Station.The UEB point model was run with the data of precipitation,wind speed,air temperature and specific humidity from the national benchmark meteorological station.The UEB distributed model was run with ERA5 reanalysis of precipitation,wind speed,air temperature and short-wave radiation and long-wave radiation in the data set.The seasonal distribution of rainfall and snow,the relationship between snow melt and temperature and other rules of snow melt runoff in the study area were analyzed.The simulation results of the point model show that: 1)the rain and snow weather determined by the model according to the critical temperature is consistent with the weather phenomenon observed by the national benchmark meteorological station;2)Snowmelt runoff mostly occurs in spring and autumn each year;3)The Nash coefficient between the simulated and measured values of monthly rainfall and snowmelt runoff depth is 0.85,and the relative error is-0.10.The simulation effect is good.4)The contribution rate of snowmelt to the total runoff in the point model was about 4%,which was significantly underestimated,mainly because the point model could not take into account the temperature distribution caused by different elevations.The simulation results of the distributed model show that: 1)due to the different temperature at different elevations,snowmelt runoff occurs throughout the year,mainly in spring and autumn,and mainly in the northern and central regions with higher elevations.2)The snow water equivalent simulated by the model changes with the temperature and reaches the peak at the lowest temperature every year;3)The snow surface temperature simulated by the model is in good agreement with the measured snow surface temperature at the meteorological station;4)The contribution rate of snowmelt to the total runoff was about 46%,and the highest value was 74% in 2016,which was higher than the actual value.In conclusion,the UEB model adopted in this paper has achieved a good simulation effect,indicating that the model has a high applicability in the source region of the Yellow River,which can provide support for the study of snowmelt runoff in areas where observation data are scarce,and the results can provide a basis for water resources prediction and planning management in the source region of the Yellow River.