Analysis Of Characteristic Snow Parameters And Snowpack Model Establishing In Northeast China

In order to reveal the variation of snow parameters and typical characteristics of northeast cold,snow melting process of micro analysis,constructs the model for the snow,the snow cover in winter and spring flood period of crop protection work during snowmelt provide experimental and theoretical basis for the utilization of water resources,this paper on the basis of relevant literature at home and abroad,for the winter snow parameters a field experiment on the northeast cold seasonal snow parameters were calculated and analyzed,and the main parameters are simulated by the distribution and change characteristics,the author tries to build the model of regional characteristics of snow.The main contents and conclusions are as follows:(1)The 2015-2016 winter snow observation experiment,measurement of the natural conditions of snow depth and snow temperature,snow density and snow liquid water content of snow parameters,at the time of 124 days of the snow cover period,the cumulative maximum snow depth value is 168mm,the maximum average snowmelt rate reached 3.20 mm/d,appeared in the late snowmelt.With the increase of deep snow snow density wave rise,the stable period of full layer density gradually stabilized between 0.1 g/cm~3 and 0.4 g/cm~3;the snow liquid water content in 0.5%~3.5%,stratified liquid water content of middle large and small fluctuations in the surface snow at the bottom;the whole layer of snow porosity average value is 72.3%,the porosity profile of the bottom of snow the porosity decreased fastest,maximum range.Snow in diameter 0.05mm to 6mm,deep frost occurred mainly in the late snowmelt in.There is little precipitation in the test period,which can not be considered in the analysis of snow characteristics in stable snowmelt period.(2)In the three layers of snow in the table,middle and bottom,the surface layer is the highest value and the largest fluctuation level in the whole accumulation snowmelt cycle,and the energy exchange is the most active.Under the influence of the interlayer hydrothermal energy conduction process,the changes of the middle and bottom parameters show a certain lag.The indicators of early stage parameters are generally low.In the middle and later stage,the soil thawing is affected by the energy input of overlying snow and the geothermal energy supply of the underlying surface.The middle layer is the hub of liquid water transport,and the two-way energy needs to be exchanged through the middle layer,and the changes of various parameters have the characteristics of delay and lag.(3)Calculation and correlation analysis of different meteorological factors that affect snow cover characteristic parameters,and three principal components were screened out by principal component analysis.The cumulative contribution rate reached 85.672%,which concentrated on the main characteristics of meteorological factors.Partial least squares(PLS)model was applied to analyze snow cover characteristic factors,meteorological factors and soil temperature and humidity conditions.The fitting equation between meteorological factors and snow cover characteristic factors was obtained,and the fitting results were feasible.(4)Correlation analysis of the three main meteorological factors and snow parameters:air temperature,liquid water content and snow temperature analysis showed significant correlation,air temperature,and moisture content as well as the snow temperature at the level of 0.01 were significantly related,Xuewen change by the change of temperature maximum shadow ring,the correlation coefficient is 0.745.To verify the temperature not only reflects the intensity of solar radiation,can also transfer energy to the snow through the turbulent exchange,is the key cause of snow melting.Through the analysis of correlation between the level of significance for water content and 0.01 solar radiation,with snow depth increases,the water content and the correlation between each layer of the solar radiation decreased gradually.As one of the snow melts the solar radiation energy input of the largest sources of variation of liquid water content directly affects the maximum.The relative humidity has a very significant negative correlation with the temperature,and the correlation coefficient of the two in the experimental period is-0.846.(5)Comparing the snow parameters under different underlying conditions,found bare soil,straw covered land,cement and grass land on four different surface,snow depth,snow temperature distribution and the most basic maximum from first to last,melting snow night,the change of water content is the most active.The factors underlying surface materials can significantly change the snow depth and snow temperature two parameters,can greatly change the degree of fluctuation of snow liquid water content,and the snow density changes smaller.(6)Comparing the snow cover parameters under different slope conditions,it is found that with the increase of slope,the maximum value of snow depth and the equivalent value of snow and water will decrease and the outlet time will be earlier.The higher the gradient,the faster the velocity of liquid water movement,the faster the snow melting process,until the peak velocity at a certain gradient.It is proved that the slope factor is an important variable of the output flow of snow.(7)To compare the snow characteristic parameters under different soil conditions,it is found that the snow depth and the cumulative snow water equivalent accumulated in the sandy soil test area are all smaller than those in the loam.This is due to the abundance of sand in sand,high permeability and poor water storage.In the process of snow melting,it will accelerate the migration of snow melting water and help to quickly discharge the snow melting water.In production practice,the ratio of soil can be adjusted according to different needs.(8)According to the law of characteristic analysis of the experimental results of snow,the mathematical model and physical model simulation of the test period of snow parameters is carried out respectively,based on RBF neural network was established based on the principle of snow depth model,after two times after optimization of snow depth model the maximum absolute error is 0.6141 cm,the maximum relative error is 5.85%,the accuracy of simulation can be controlled within 6 mm.Using the SHAW model,frozen snow depth and snow depth and snow water equivalent energy of physical simulation,it was found that the simulation results accord with the actual law,from the angle of rich boundary conditions further improve the plate model of snow.In summary,for distribution and its influencing factors of northeast cold snow properties analysis,to understand the Northeast winter snow covered the actual variation and retreat,contribute to the potential by mining in northeast area in winter snow,to achieve a reasonable disaster prevention and effective utilization of the resources of snow cover.It is of great significance for improving the safety of crop production and the safety of water resources in Heilongjiang province.