| Soil moisture is an important part of the study of land surface eco-hydrological cycle and soil parameters,With the progress of science and technology and the great strides of The Times,it drives the progress of remote sensing modeling technology and the development of remote sensing inversion theory system gradually mature,Therefore,the study of surface soil moisture content inversion based on satellite remote sensing image data becomes an important observation means to understand the changes of vegetation ecological environment.At present,many domestic and foreign researchers have shifted their research focus to soil moisture research based on multi-source remote sensing data,and made a lot of experimental research and made breakthrough progress.However,in the study area,soil water inversion is mainly carried out in areas with low vegetation coverage,while soil water inversion research is relatively rare in areas with high vegetation coverage.Therefore,it is imperative to conduct soil water inversion research in areas with high vegetation coverage.Huize county covers a wide area of vegetation,and the terrain is mainly mountainous.The local topography,soil and vegetation cover have a complex relationship,which can be used as a typical region in central Yunnan for research.In this paper,the advantages of single remote sensing data(GF-5 VIMS data and Landsat8 OLI/TIRS data)are combined to form a new multi-source remote sensing combined data(GF-5 VIMS thermal infrared data and Landsat8 data)OLI data were used to invert surface soil moisture in the study area,and the advantages and disadvantages of single remote sensing data and multi-source remote sensing combined data on surface soil moisture in the study area were compared and analyzed.Firstly,land surface temperature inversion was carried out based on single remote sensing data and multi-source combined remote sensing data.Then calculate NDVI,NDMI and other vegetation parameters,The two-dimensional characteristic space of land surface temperature and vegetation index was established,Then,the TVDI soil water inversion model was used to invert soil water in the study area,And compare the difference between soil water inversion results obtained from different types of data and select the better inversion results to analyze the spatial distribution of soil water inversion detection in the study area and discuss the control scheme.The main research results show that:(1)Two types of data,single remote sensing data and multi-source combined remote sensing data,were used to invert surface soil moisture in the study area,It was found that the inversion effect of GF-5 VIMS and Landsat8 OLI data was weaker than that of Landsat8 OLI/TIRS data,In Landsat8OLI/TIRS data,the results of surface temperature inversion using radiative transfer equation method(10 bands)and NDMI constitute the characteristic space results of soil water content inversion are the best.Aiming at the study of vegetation water content estimation,the correlation between land surface temperature and vegetation water content was calculated by analyzing the relationship diagram of land surface temperature and vegetation water content composed of two indices,The results show that Ts-NDMI is better for estimating vegetation water content in the study area.(2)In August,the proportion of wet soil,normal soil,light drought soil,dry soil and severe drought soil were 4.68%,32.4%,50.92%,11.53% and 0.47%,respectively.More than half of the soil area is lightly dry,and more than 10% of the soil area is dry.(3)The inversion value of TVDI was negatively correlated with vegetation water content and VHI.The degree of drought would affect the health degree of vegetation,and soil drought would lead to the decrease of vegetation water content and thus the decline of vegetation health degree.The inversion value of TVDI was negatively correlated with soil-regulated vegetation index,and the inversion value of TVDI was positively correlated with bare soil index.Therefore,soil water loss in the study area can be alleviated by reducing bare soil area by planting vegetation.The inversion value of TVDI is negatively correlated with elevation,and the surface temperature is also negatively correlated with elevation.Elevation has an inhibitory effect on soil water loss,while elevation decreases surface temperature and soil water loss.Finally,on the basis of the above conclusions,this paper puts forward the corresponding control suggestions for the present soil drought situation in Huize County. |
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