MODIS vegetation indexes (EVI and NDVI)
MODIS is an EOS sensor designed to measure biological
and physical processes on a global basis every 1 to 2 days
and will provide long-term observations from which an
enhanced knowledge of global dynamics and processes
occurring on the surface of the earth and in the lower
atmosphere can be derived (King & Greenstone, 1999). The
first sensor was mounted on Terra launched in December
1999 and began to provide MODIS Products since the year
2000. Two MODIS VIS, the normalized difference vegetation
index (NDVI) and the enhanced vegetation index
(EVI), are produced globally over land at 1 km and 500 m
resolutions and for 16-day compositing periods. The
MODIS NDVI is referred to as the bcontinuity indexQ in
relation to the existing 20+ year NOAA–AVHRR-derived
NDVI time series, and these should be extended by MODIS
data to provide a longer-term data record for use in
operational monitoring studies.
The enhanced vegetation index (EVI) is an doptimizedT
vegetation index with improved sensitivity in high biomass
regions and an improved vegetation monitoring characteristic
via a decoupling of the canopy background signal and a
reduction in atmospheric influences