| Remote sensing retrieval of soil moisture using ENVISAT—ASAR and MODIS images in vegetated areas of Huanan |
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| DOI：10.7606/j.issn.1000-7601.2008.03.07 |
| Key Words: SAR soil moisture backscatter coefficient |
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| Abstract: |
| It has been greatly applied in agricultural sciences to retrieve large area soil moisture information accurately and promptly．The study area is located in Xuwen County which has regional features prominently． Dua-l polarization ENVISAT-ASAR and MODIS images were used to retrieve soil moisture．The estimation of vegetation water content （VWC） of experiment regions was performed using MODIS-derived normalized difference water index （NDWI） near the experiment date．Compared with NDVI NDWI is more suitable to high vegetation covering in the study area．NDWI can reflect changes when NDVI is saturated along with cropgrowth． In the end the vegetation effects were eliminated from the total ENVISAT-ASAR backscattering coefficients by using “water-cloud” model and then we simulated the relation between the backscattering coefficient of bare soil and ground measured soil moisture after eliminating vegetation effect．The results showed that VV polarization fitting is better than HH polarization with correlation coefficient 0．865 in VV polarization and 0．676 in HH polarization．The estimation of soil moisture content in vegetated areas should be further improved in the future． |