Comparison of Earth Observing-1 ALI and Landsat ETM+ for crop identification and yield prediction in Mexico

This paper presents a comparison of Earth Observing 1 (EO-1) Advanced Land Imager (ALI) and Landsat-7 Enhanced Thematic Mapper Plus (ETM+) images collected over an agricultural region in northwest Mexico. Across 115 fields with a range of cover types, radiance measurements collected by ALI were within 3% of ETM+ for all five common bands. Crop discrimination was significantly improved with ALI compared to ETM+, with an increase from 85% to 95% accuracy for distinguishing maize from wheat fields. This improvement was attributed to the greater SNR in ALI, as well as the unique information content of ALI band 4p (0.84–0.89 m), which may be due to sensitivity to canopy water content. Yield predictions from reflectance-calibrated data did not reveal significant differences between the sensors. The greatest distinction between ALI and ETM+ was observed in the panchromatic band, with ALI providing more detailed information on interand intrafield radiance differences, which show promise for precision agriculture applications. We conclude that ALI meets or exceeds ETM+ performance for agricultural applications evaluated here, thus providing a plausible option for continuity of the valuable Landsat record.