As a part of the NASA-centred international Earth Observing System, two
MODIS instruments (Salomonson et al. 1989) have been launched to provide
information for global studies of atmosphere, land, and ocean processes. The first
was launched on 18 December 1999 on the morning platform called Terra, and the
second was launched on 4 May 2002 on the afternoon platform called Aqua. The
Terra overpass time is around 10:30am (local solar time) in its descending mode
and 10:30pm in ascending mode. The Aqua overpass time is around 1:30pm in
ascending mode and 1:30am in descending mode. The strengths of the MODIS
instrument include its global coverage, high radiometric resolution and dynamic
ranges, and accurate calibration in visible, near-infrared and thermal infrared
bands. The Terra MODIS data have been used to generate science data products
for more than two years and these science data products are available to the public
free of charge. A consistent reprocessing has been made for Terra MODIS data
since November 1999 to generate science data products (version 3) in either