Dynamic Change Of Soil Surface Moisture Content In Shendong Mining Area Based On TVDI

Soil surface moisture content is an important index to monitor land degradation,and it plays a vital role in the study of vegetation growth,land reclamation,ecological restoration and other fields.The coal mining activities in the mining area often cause the mining area to be in the state of water shortage,which will cause a series of ecological environment deterioration problems if not treated.The traditional soil moisture content monitoring method consumes a lot of material resources,manpower and financial resources,which can not meet the need of large-scale monitoring.Therefore,it is of guiding significance for land reclamation and ecological restoration of mining area to monitor the dynamic change of soil surface moisture content based on remote sensing technology in a large range,high aging and strong contrast,and master its dynamic change rule,natural influencing factors and the influence of coal mining collapse.In this thesis,the soil surface moisture content(0 ～ 10cm)in Shendong Mining Area is taken as the research object,and the field sampling,laboratory test soil surface moisture content measured data,Landsat,MODIS remote sensing satellite,DEM elevation,Based on meteorological data and supported by Remote Sensing(RS)and Geographic Information System(GIS),Using the Temperature Vegetation Drought Index,(TVDI)remote sensing inversion model,using pixel dichotomy model,geographical detector model,center of gravity migration and transfer matrix,M-k test,linear trend analysis(Bslope),deviation analysis,significance analysis and other research methods.This thesis analyzes the spatio-temporal evolution of soil surface moisture content,the influencing factors of dynamic change and the response of coal mining collapse to soil surface moisture content in Shendong mining area in recent 30 years.The main research conclusions are as follows:1.The TVDI model is inversely proportional to the soil surface moisture content,the fitting coefficient is 0.73,and the average inversion accuracy is 78%.Apparent Thermal Inertia(ATI)model was apparent proportional to surface moisture content,with a fitting coefficient of 0.13,and an average inversion accuracy of 57.4%.The inversion accuracy of soil surface moisture content(0 ～ 10cm)based on TVDI model is higher and the inversion effect is good.2.TVDI in Shendong mining area has the lowest value from June to September every year.The average annual TVDI fluctuated between 0.56 and 0.69,with the highest in 2002,which began to decline year by year after 2002,and the lowest in 2018,which was 0.56.The average inter-annual decline rate of TVDI is 0.02/30 a.The spatial variation of TVDI grade over time showed that the moist and wetter areas showed an increasing trend,while the normal,arid and arid areas showed a decreasing trend.The increasing trend area of soil surface water content was higher than the decreasing trend area,which was consistent with the time change trend.3.Precipitation,soil type and NDVI were the main influencing factors of TVDI.The two-factor interaction was enhanced by two-factor or two-factor nonlinear,and both were stronger than the single-factor interaction.TVDI was negatively correlated with the main influencing factors(precipitation and NDVI).The dynamic change of soil surface moisture content is usually the result of synergistic action of many factors rather than a single factor.4.The variation trend of the mean TVDI of mines distributed within the same evaluation unit is basically consistent.The soil surface moisture content in the aeolian sand area reaches the lowest value within 1-5 years of mining,and the soil surface moisture content in the aeolian sand area is the lowest before mining in the evaluation unit of the aeolian sand area intersecting with the hard beam and the hard beam site.At the same time,soil surface moisture content in subsidence area was lower than that in unsubsidence area.Soil surface moisture content was not significantly related to the length of reclamation period,but more closely related to reclamation intensity and soil and water conservation measures.