Mechanism Of Water Vapor Heat Transport In Vadose Zone Of Badain Jaran Desert

Badan Jilin desert has poor climate conditions,few rainfall,strong evaporation,less vegetation coverage and extremely fragile ecological environment.Therefore,it is of great significance to study the water migration in the gas bearing zone of Badan Jilin desert and reveal the mechanism of water migration in the gas bearing zone for exploring the source of groundwater in Badan Jilin desert and improving the local ecological environment.Based on the data of field experiment,the paper studies the water migration law of the gas-bearing zone in Badan Lake area of Badan Lake Desert in Badan Jilin desert by analyzing the data and combining with numerical simulation.In this paper,the desert vadose zone is studied by in-situ test,indoor test and numerical simulation.The influence of different groundwater level buried depth on water migration in the gas bearing zone is analyzed.The relationship between temperature and water migration law in the vadose zone is studied.The coupled model of water vapor and heat in the desert gas belt is constructed to reveal the law of infiltration and evaporation of atmospheric precipitation in desert area,which provides the basis for the evaluation of groundwater resources in desert area.Finally,the following conclusions are drawn.(1)The variation of water content in the aeration zone in season generally shows that the shallow water content fluctuates with the seasons,and the water content of deep soil fluctuates little with the seasons with the depth increasing.Because of the high evaporation of desert temperature,the water content of the whole shows that the shallow water content is lower,and the deep water content is higher.(2)The temperature of each depth in the aeration zone is the same with the time,and the trend is basically the same with the atmospheric temperature.It is that the temperature in summer increases and the temperature in winter decreases.The soil temperature in the whole research depth range is affected by the atmospheric temperature,and the effect of soil temperature decreases with the increase of soil depth,and there is a certain delay.The change of soil temperature in shallow layer is more violent in profile,and the fluctuation of deep soil is smaller,indicating that seasonal effect decreases with the increase of depth.(3)The shallow layer of the temperature in the vadose zone has a great change in water content,and the water content has a positive correlation with the temperature,and the correlation coefficient is close to 1.(4)The groundwater evaporation and infiltration law is studied by selecting different groundwater level buried depth.When the groundwater depth is 0.75 m,the recharge is the largest,and the groundwater recharge is zero when the groundwater depth reaches 2m.The evaporation of groundwater surface decreases sharply first and then slowly with the increase of groundwater depth.When the buried depth of groundwater level reaches 3.7m,the groundwater is not affected by evaporation,and its evaporation is zero.