| The Bailong River Basin is the Yangtze River water upstream areas and ecological barriers, which is one of the most serious areas of debris flow, and the ecological environment is very fragile. In the early period of debris flow, the soil moisture as a mudslide effective organization form of precipitation is one of the key factor of hydrology in the formation of debris flow. Therefore, it has important scientific significance for the formation mechanism of debris flow in Bailong River Basin and understanding the changes in the watershed soil moisture conditions. In addition, soil moisture is an important indicator of soil quality monitoring and one controlling factor for crop growth. Soil moisture is not only the direct water resources for vegetation and crops, controling the agricultural productivity, but also controling and adjustging the interactions between the atmosphere and the ground, has the vital significance to climate change, weather forecasting, hydrological simulation, and agricultural production and so on.The traditional soil moisture monitoring is alwayls dot distribution based on the manual or automatic observation, which cannot reflect the spatial distribution of soil moisture status in certain areas because of the certain limitation.With the development "3S" technology, it provides a possibility for a large-scale, real-time and dynamics monitoring of soil water. Therefore, making use of the soil moisture RS inversion model, to carry out quantitative inversion of soil moisture content based on the technology of RS technology, not only help enrich and improve the method of risk assessment and the theory of debris flow occur, having a great significance for evaluation of ecological and environmental protection and reconstruction of great significance, but also it has important practical significance and scientific value for the construction of agricultural production and the optimal allocation of groundwater resources and sustainable ecological and economic development in the study area.Based on the current basis of the optical remote sensing inversion model of soil moisture and a comprehensive analysis of the study area’s topography, soils, vegetation, considering the results of the spatial scale inversion requirements, The research try to retrieve the Soil Moisture in the first paragraph Bailong River Basin of Wudu key research area by using LandsatETM, ASTER data in April in2013, and combined MODIS1B data and DEM data with field sampling data.The paper choicing the temperature vegetation drought index (TVDI) model to construct the0-20cm,20-40cm,40-60cm and0-40cm,0-60cm five soil depth soil moisture inversion model based on two types of data, at the same time.verifying and comparing the accuracy of the inversion results. The results show that the soil moisture inversion results based LandsatETM+data obtained at different depths with higher precision, so the reseach choose LandsatETM+data to build TVDI regression model, in order to botain the soil moisture throughout the Bailong River basin, and ultimately got the whole basin soil moisture spatial distribution of the results, and conducted a precision verification.By the spatial analysis function of GIS and the single factor analysis of variance method, respectively, the reseach analyzes the influence of land use type,slope and Topographic Wetness Index respectively.The analysis found that a different aspect, and land-use type has a significant influence on soil moisture, the average soil moisture in different slope direction appear the trend of cloudy slope> half cloudy slope> half sunny slope> sunny slope, and showed the characteristics of the forest land> grassland> farmland, besides, industrial and mining resident land due to many for urban and rural construction land, soil moisture is lowest.At last, Combining TVDI, TWI, slope and land use type, the paper makes use of the method of multiple linear regression to construct soil moisture inversion model in different depths and verified the accuracy of the model. In conclusion, the research takes the two methods of inversion of TVDI regression model and integrated regression model to obtain the soil moisture spatial distribution of0-20cm,20-40cm,40-60cm,0to40cm and0to60cm soil depththe in bailong river valley. |
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