The Seasonally Frozen Infiltration Mechanism Research During Snowmelt Period On The Northern Slope Of Tianshan

Permafrost is variety of geotechnical and soil that temperature at0℃or below0℃, containing ice. Seasonally frozen ground is the soil that winter freeze andsummer all melted. The region of seasonally frozen that deeper than50cm accountedfor46%of land area. The region of seasonally frozen that depth is less than50cmaccounted for2i%of land area. Seasonally frozen ground in our country is mainlydistributed in the north of latitude30°arid and semi-arid areas. Soil infiltrationcapacity, including under seepage flow and infiltration intensity, is a loss item ofrunoff, and has a direct impact on the proportion of the surface and subsurface runoff.Seasonal frozen soil infiltration capacity has an important significance to the soilwater storage capacity and snowmelt runoff in Arid and Semi-Arid Regions. Seasonalfrozen soil infiltration capacity affect on the next year’s irrigation water demand andirrigation water available. In Arid and Semi-Arid Regions, The spring floods almostcome from glaciers and snow melt water. And as snowmelt water infiltration media,seasonally frozen ground is an important factor for snowmelt runoff simulation.Research of seasonal permafrost infiltration mechanism in Arid and Semi AridRegions can provide theoretical support for the snowmelt runoff simulation and floodwarning.This article using data obtained from field test site in JunTangHu river basin andlaboratory test to analyzed physical parameters, reduced infiltration characteristics,Infiltration process and infiltration factors of seasonally frozen soil in study area. Andthis article simulated the seasonal frozen soil infiltration process during snowmelt.The results showed that:(1)The study area soil is silt loam. Soil at depth of0to40cmchanged more and more closely, and the permeability is reduced with increasing depth.Reduced infiltration capacity of seasonally frozen soil is inversely proportional to theair temperature, while reduced infiltration capacity of seasonally frozen soil isproportional to the depth of frozen soil and soil.(2) In the early snowmelt, the value of infiltration is smaller. There is snowmelt infiltration when the air temperature at theheight of one day. Infiltration processes stepwise. In the medium-term snowmelt, theinfiltration has higher value. All day has snowmelt infiltration. In the later snowmelt,the snowmelt infiltration has increased substantially. Infiltration happened all day.(3)Diurnal variation of the air temperature, the positive temperature cumulative, soiltemperature and soil moisture is the influencing factors of snowmelt infiltration.Infiltration and air temperature changes in the same trend during Snowmelt. In theearly snowmelt, soil infiltration mainly affected by the diurnal variation of airtemperature. In the later snowmelt, soil infiltration affected by positive temperatureaccumulation and the combined effect of the diurnal variation of air temperature. Soiltemperature changed proportion of water and ice and depth of frozen soil throughchanged Three-phase conversion of water, thereby affecting snowmelt infiltration.(4)Soil moisture content and the positive temperature cumulative have a large correlationat different depths of soil. They have linear and exponential relationship.(5)Thisarticle established a run automatically infiltration model. This article established arelationship between positive temperature cumulative and infiltration through therelationship of soil moisture content and positive temperature cumulative. Positivetemperature cumulative used to simulate the infiltration process as a model variable.So the infiltration model got rid of space and time constraints of human observationaldata. Simulated and measured curves have the same trend. Simulated value ofinfiltration can reach accuracy requirements.