Response Of Ground Temperature To Temperature Change At Different Depths Of Burial In Cold Regions

With climate change on a global scale,the degradation and melting of permafrost in cold regions is serious,and permafrost is extremely sensitive to climate change in cold regions.The freezing and thawing of permafrost has different degrees of impact on people's lives,engineering construction and climate change warning in cold regions,and it is necessary to study the response of ground temperature to temperature change in cold regions.Land is the most basic resource base for human production,life and development.If the allocation of land resources can be reasonably optimised,then the effective utilisation of land resources will be greatly enhanced.Permafrost,as an important component of the cryosphere,has long been regarded as a very important land resource.The development and degradation of permafrost is very directly related to climate change.It is essential to explore and understand the temperature response relationship of soils in cold regions to temperature.Using a cold ground temperature monitoring device and a 1.5m louvered box buried in the hydrological station of Songling District,Daxinganling University,the ground temperature and air temperature data measured during the 80-d permafrost development period from 13 October 2020 to 31 December 2020 were analysed using bivariate analysis to monitor and analyse the response of ground temperature to air temperature changes during the permafrost development period in this study area.The results show that The results show that.(1)The response of ground temperature to temperature changes during the period of permafrost development in the Songling District of the Daxinganling differed at different depths,and the correlation between ground temperature and temperature was significantly correlated,and the correlation decreased with increasing depth.(2)The correlation coefficient between the average daily surface temperature of the last 5 days and the ground temperature at different depths is the largest,with a value of 0.997;the second is the correlation coefficient between the average daily surface temperature of the last 3 days and the ground temperature at different depths,with a value of 0.996 only;the third is the correlation coefficient between the average daily surface temperature and the ground temperature,with a value of 0.991 only.The accumulated temperature of air temperature was positively correlated.(4)Soil freezing began to occur in the Songling District of the Daxinganling Region on November 2,2020,and the freezing depth gradually deepened,reaching a soil freezing depth of 142.4 cm by December 31,2020,with an average daily freezing rate of 2.37 cm/d.Among them,within the first 9 d of the soil starting to freeze(November 2,2020-November 10,2020),the freezing rate was the largest at 5.05cm/d,the average daily freezing rate was essentially the same at 0.74cm/d from 11 November 2020 to 22 December 2020,and increased from 24 December 2020 to 31 December 2020 at 0.975cm/d.(5)50cm,100 cm,200cm,300 cm,400cm,500 cm burial depth ground temperature change and surface temperature change trend is similar,but the surface temperature negative correlation coefficient is higher in about 15 days,while the other soil layer temperature in about 20 days,especially 300 cm soil temperature autocorrelation in about 18 days,400-00c5 m more stable in 20 days,the above not only indicates the existence of a half-month negative correlation trend in soil temperature,but also reaches a relatively stable stage after 300 cm,and it can be assumed that the existence of an active layer of soil at this depth exists.