Comparison of two methods for extracting surface soil moisture from C-band radar imagery

The integral equation method (IEM) model and a newly defined delta index were used to estimate near surface soil moisture from C-band radar satellite imagery in a semiarid rangeland in southern Arizona, USA. Model results were validated against soil moisture measurements made in the field at the time of satellite overpass. The IEM model performed poorly in this environment possibly due to abundant near-surface rock fragments which were not considered in the model. The delta index performed better than the IEM model and was shown to work with both ERS and Radarsat imagery. Additionally the index was simple to implement and implicitly accounted for both rock fragments and surface roughness