Use Of Radarsat₂Four Polarization Images In Hetao Irrigated Soil Salinity Inversion

Soil salinization is an important factor affecting agricultural production in cold, dry areas. Soil salinization has a serious impact on socio-economic and agro-ecological. Today, land resources are extremely scarce and agricultural land security, food security has become a very important issue. But soil salinization is constantly devouring million hectares of farmland in Hetao area.Soil salinization has become a worldwide problem. Today, land resources are extremely scarce, food security problem sweeping all the Corners of the world. So the protection of arable land and its resources are urgently. Compared to conventional technology, remote sensing with real-time, fast, macroscopic characteristics, can quickly get to the macro range salted distribution, changes extremely trends, which has become an important means of saline land information extraction. Because visible light, infrared remote sensing has some limitations, but with all-weather radar, penetrating characteristics. So, radar remote sensing become fast, large-scale extraction of Saline Soil Information technology.In this paper, data from Canadian satellite Radarsat-2, the most advanced C-band Synthetic Aperture Radar (SAR) is used to soil salinity research.First of all, there are three different methods are used for Radarsat-2data processing to get the Sigma Nought of Radarsat-2. By comparing different Sigma Nought get from different methods and different way to extract it, via point position get by the use of GPS, to find the most conducive way to inversion. At last, verified that "Resample will have some impact on inversion of soil salinity" and get the result that "When the multilooking causes resample more times, you should select the multilooking"Secondly, ways are used to improve the retrieval accuracy such as considering the relevant factors soil moisture, radar incidence angle, etc. Although soil temperature data obtained by MODIS ultimately failed to participate in soil salinity inversion process, but for future research to provide a reference. When, considered separately soil moisture, radar incidence angle and other factors, the correlation coefficient R scattering coefficient and soil salinity were between radar upgrade from the original0.706to0.737and0.718.Finally, the article gives the salt content of the soil after considering the Radarsat-2four-polarized images Sigma Nought, angle of incidence, soil moisture content and other data inversion model. This model has a correlation coefficient of salinity R=0.937, adjusted R2=0.858.In summary, the use of Radarsat-2data can effectively extract the Hetao Plain Saline Soil Information. After many as the"radiation treatment can significantly improve image resolution Radarsat-2. while improving the resolution of radiation can significantly improve the relevance of the scattering coefficient and surface soil salinity between the Radarsat-2; less resampling can improve the relevance of Radarsat-2backscattering coefficient and surface soil salinity between. The time factor and the radar backscatter coefficients relating soil moisture, radar incidence angle into account, will improve the relevance of the Radarsat-2backscattering coefficient and surface soil salinity between.