Soil Moisture Retrieval Over Early Corn Covered Area Using Radarsat-2 and Terrasar-X Data

摘要

The main objective of this study is to develop a semi-empirical soil moisture retrieval approach using SAR (Synthetic Aperture Radar) and optical satellite data for early corn covered areas. Firstly, the water cloud model was employed to eliminate the effects of vegetation canopy, thus to obtain the bare soil backscatter coefficient associated with soil moisture. Then, against the underdetermined system for soil moisture estimation, the calibrated integral equation model with two soil surface parameters was integrated to construct soil moisture retrieval scheme in combination with Radarsat-2 and TerraSAR-X data. At last, soil moisture can be derived by the minimization of the comprehensive cost function. Based on the field measurements and multi-sensor SAR data acquired on 15 June 2015 over agricultural area, quantitative evaluation of the developed approach was implemented. The results indicate that accurate soil moisture was obtained by the developed approach over the corn covered areas. The root mean square error of the estimated results are less than 0.05 cm^{3/cm3, and determination coefficients are greater than 0.7.}