Multitemporal monitoring of soil moisture with RADARSAT SAR during the 1997 Southern Great Plains hydrology experiment

Multitemporal RADARSAT Synthetic Aperture Radar (SAR) imagery was evaluated for monitoring soil moisture during the Southern Great Plains 1997 Hydrolo gy Experiment (SGP97). Over the 1-month experiment a total of 10 RADARSAT ( C-band; 5.3 GHz; HH polarized) acquisitions were obtained. After co-registr ation of the images, the dependence of the backscattering coefficient (sigm a degrees) on incidence angle (theta) was evaluated. An angular correction scheme was applied to the data and the correlation of sigma degrees values with volumetric soil moisture measurements was determined. A high positive correlation between the two was observed for wheat stubble fields, whereas no correlation could be observed for pasture fields. A change detection app roach yielded a correlation of soil moisture changes to sigma degrees chang es for wheat stubble fields, indicating the potential of this method for so il moisture monitoring.