Providing crop information using RADARSAT-1 and satellite optical imagery
In 1997, the Canada Centre for Remote Sensing acquired RADARSAT-1, SPOT and IRS-1C imagery over an agricultural site in western Canada. These data were used to address the information content of RADARSAT-1 imagery for mapping crop type and for providing information on crop condition, and to explore the implications of crop growth stage on crop monitoring with radar imagery. The use of radar for crop mapping is particularly attractive because of its all weather capability and the sensitivity of microwaves to canopy structure and moisture. Results from this study indicated that multi-date RADARSAT-1 imagery, with or without satellite optical imagery, can provide accurate information about crop types, although timing of image acquisition was important. Regression analysis established that some indicators of crop vigour - in particular leaf area index and crop height - were correlated with backscatter. The highest correlations were for wheat and potatoes. However, backscatter was insensitive to variations in corn growth and only moderately sensitive to differences in indicators of canola crop condition. Nevertheless, this study clearly demonstrates that multi-temporal RADARSAT-1 imagery can be used to provide useful crop information.