Upscale integration of normalized difference vegetation index: the problem of spatial heterogeneity

Abstract
The correspondence between the normalized difference vegetation index (NDVI) calculated from average reflectances, MNDVI , and NDVI integrated from individual NDVIs, INDVI , by simulating AVHRR data from high spatial resolution SPOT 1 Haute Resolution Visible radiometer and Landsat Thematic Mapper data is analyzed. For the considered sites, located in tropical West Africa and temperate France, and the scales analyzed, 300-1000 m, a strong correlation exists between the two types of index. The relationship is almost perfectly linear, with a slope depending slightly on the variability of the vegetation cover. Effecting the scale change using MNDVI instead of INDVI does not introduce significant errors