Comparison of image data acquired with AVHRR, MODIS, ETM+ and ASTER over Hokkaido, Japan Original Research Article

Comparisons are made from data acquired by four multi-spectral sensors (Landsat/ETM+, Terra/ASTER, Terra/MODIS, and NOAA/AVHRR) over Kushiro Marsh in Hokkaido, Japan, on September 26, 2001. There is good agreement in the spectral characteristics of the Digital Numbers (DNs) between ETM+ and ASTER. Equations relating the Landsat/ETM+ digital number to that of the Terra/ASTER are developed. To eliminate various environmental effects, the Normalized Difference Vegetation Index (NDVI) is computed from the data of the four sensors. Typical values of the NDVI for several land cover types are obtained. The NDVI values for broad-leaf forest indicate the NDVI derived from MODIS is the largest followed by those of ETM, ASTER and AVHRR. The ranges of respective NDVIs reflect the spatial resolution. To reveal the effect of the sensorsʹ spatial resolution, simulated data are generated from the higher spatial resolution (small size pixel) data to match the lower spatial resolution (larger size pixel) data. Comparisons of NDVIs for the simulated pixels indicate that the MODIS NDVI has the largest minimum, mean, and maximum numerical values while the ASTER NDVI indicates the opposite characteristics.