The growth of the available archives of satellite
data has made it possible to study the spatial and
temporal changes in vegetation changes.
The longest consistent satellite derived vegetation
records are from the NOAA (National Oceanic and Atmospheric Administration)
series of AVHRR (Advanced Very High Resolution Radiometer) sensors.
NOAA-AVHRR has taken almost daily images of the Earth's surface at 1.1 km resolution
for nearly 25 years.
