This spectacular Moderate Resolution Imaging Spectroradiometer (MODIS)
“blue marble” image is based on the most
detailed collection of true-color imagery of the entire Earth to date.
Using a collection of satellite-based observations, scientists and
visualizers stitched together months of observations of the land
surface, oceans, sea ice, and clouds into a seamless, true-color mosaic
of every square kilometer (.386 square mile) of our planet. Most of the
information contained in this image came from MODIS, illustrating MODIS
outstanding capacity to act as an integrated tool for observing a
variety of terrestrial, oceanic, and atmospheric features of the Earth.
The land and coastal ocean portions of this image is based on
surface observations collected from June through September 2001 and
combined, or composited, every eight days to compensate for clouds that
might block the satellites view on any single day. Global ocean
color (or chlorophyll) data was used to simulate the ocean surface.
MODIS doesnt measure 3-D
features of the Earth, so the surface observations were draped over
topographic data provided by the U.S. Geological Survey EROS Data
Center. MODIS observations of polar sea ice were combined with
observations of Antarctica made by the National Oceanic and Atmospheric
Administrations AVHRR sensorthe Advanced Very High Resolution
Radiometer. The cloud image is a composite of two days of MODIS imagery
collected in visible light wavelengths and a third day of thermal
infra-red imagery over the poles.
A large collection of imagery based on the blue marble in a variety of
sizes and formats, including animations and the full (1 km) resolution
imagery, is available at the Blue Marble page.