Study On Soil Moisture Inversion Of Sparse Vegetation Cover Conditions Based On Sar Data

Soil moisture is an important part of the soil, it plays an important role in theland-air interface between the material and energy exchange between the hydrosphere,biosphere and atmosphere interaction has an important impact. Soil moisture is animportant parameter of the basic conditions for crop growth and crop yield forecasting,it′s an important indicator for monitoring land degradation and drought forecasting,but also key elements of climate, hydrology, ecological and agricultural systems. Soilmoisture is an important element of the entire planet's ecosystem, it is one of theimportant conditions of the animals, plants, and the survival of the control of thelanding to the water cycle, carbon cycle and atmospheric circulation, it is inputparameters in the various research of the many hydrological models, climateimportant model, the ecological model. Therefore, in the large-scale and global scalesoil moisture monitoring is of great significance and value. There is many traditionalmethod of measuring soil moisture, such as the gravimetric method, the resistancemethod, soil hygrometers, these measurements are based on the measurement pointduring the field measurements need to build high density network of observationpoints, and traditional methods in the field of actual operation and subsequent dataprocessing are quite complicated, take a lot of inconvenience to the agriculturalproduction and ecological environment warning. With the development and progressof remote sensing technology, remote sensing technology has demonstrated manyadvantages in the monitoring of soil moisture, one of the main advantages of itsmonitoring is wide range, high efficiency, low cost, but also to carry out long-term,dynamic monitoring, and thus have widespread concern and attention of researchers.Microwave remote sensing of soil moisture monitoring can monitor the ground0~5cm depth soil moisture, microwave remote sensing technology of extraction of soilmoisture spatial distribution, and therefore, the actual soil moisture monitoring, microwave remote sensing of soil moisture monitoring has broad applicationprospects. Many scholars study shows that active microwave can make up for theother methods, the lack of soil moisture monitoring applications such as traditionalsoil moisture monitoring method, optical remote sensing and passive microwaveremote sensing method for the large area, large-scale soil moisture monitoringprovides a new methods and channels.In this study, first the use of AIEM model to simulate different surface roughnesscase, the relationship between the radar scattering coefficient and surfaceparameters.in the simulation process, a combination of roughness parameter Rs=s3/l2have be proposed, the roughness is two roughness parameters R ms height of s andcorrelation length l combined. Second, it analyzes the relationship between thescattering coefficient and soil moisture, surface roughness parameters in a given radarsystem parameters and surface parameters under the conditions of radar, establishedthe experience in soil moisture estimation model apply to the different angle ofincidence range under the conditions of VV and VH polarization; Finally, we use thedata obtained by RADAR-SAT2to make an application and validation of theestablished empirical model in Weigan-Kuqa River delta oasis. The results showthat good correlation between the inversion and measured values of soil moistureinversion empirical model established in this study, coefficient of determination of0.8109, indicating that the empirical model of this study to establish the soil moistureestimation for Sparse vegetation cover surface soil moisture estimation more reliable.