Intercalibration and Evaluation of ResourceSat-1 and Landsat-5 NDVI

ResourceSat-1 is a designated alternative to Landsat should the existing TM (Thematic Mapper) and ETM + (Enhanced Thematic Mapper Plus) sensors fail prior to the successful launch of Landsat 8 in late 2012. However, to enable integration of ResourceSat-1 into the many existing long-term Landsat projects around the world, practicable similarity must be demonstrated. To quantify the potential for ResourceSat-1 to satisfy some of the needs of the remote sensing community, Normalized Difference Vegetation Index (NDVI) values derived from Landsat-5 were compared to NDVI values derived from ResourceSat-1. An intercalibration equation that converts ResourceSat-1 NDVI values to equivalent Landsat-5 NDVI values was derived thereby enabling direct comparison between the two sensors. Comparisons were made using imagery spanning a 3-year time period. Prior to intercalibration, NDVI values were highly correlated (mean R-2 > 0.73) but statistically different (P < 0.001). Following intercalibration, the resulting indices were statistically inseparable (P >= 0.56). The intercalibration technique described in this paper represents an easily repeatable process that demonstrates practicable similarity between ResourceSat-1 and Landsat-5 imagery.