Submitted to: International Journal of Remote Sensing
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/1/2000
Publication Date: 4/1/2001
Citation: Interpretive Summary: Results from an analysis of multi-temporal satellite synthetic aperture data, RADARSAT, have provided an excellent insight on the sensitivity of backscattering coefficient to surface soil moisture for the conditions of the study. The influence of incidence angle, vegetation density and surface roughness on the backscatter signal was demonstrated. Results were consistent with prior experimental results which showed a high sensitivity for a C-band system to near-surface soil moisture under sparsely vegetated conditions. The capability of RADARSAT to make observations using different viewing angles by changing its beam mode makes it unique as a SAR satellite platform, and allows observation of an area with a short revisit time. The availability of a series of 10 RADARSAT scenes over the one month experiment period presented an excellent opportunity to study temporal variability of soil moisture. From these results it appears that RADARSAT data has a strong potential for multi-temporal meso-scale soil moisture monitoring. These results may prove to be of value in both high and low resolution applications in hydrology and agriculture.
Technical Abstract: Multi-temporal RADARSAT synthetic aperture radar (SAR) imagery was evaluated for monitoring soil moisture during the Southern Great Plains 1997 Hydrology Experiment (SGP97). Over the one month experiment a total of 10 RADARSAT (C-Band; 5.3GHz) acquisitions were obtained. After co-registration of the images, the dependence of the backscattering coefficient on incidence angle was evaluated. An angular correction scheme was applied to the data and the correlation of backscattering coefficient 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 approach yielded a strong correlation of soil moisture changes to backscattering changes for wheat stubble fields, indicating the potential of this method for soil moisture moinitoring.