MODIS (Moderate Resolution Imaging Spectroradiometer) is the key remote sensing instrument carried onboard NASA's Earth Observing System (EOS) satellites, Terra and Aqua. Terra began collecting science data in February 2000; this was followed by Aqua's successful launch in May 2002. Terra and Aqua fly at about 705 km (438 mi) above the Earth and complete an orbit every 108 minutes. GINA has been receiving and archiving MODIS data from Terra since August 2002 and from Aqua since January 2003.

MODIS is a multi-disciplinary instrument designed to measure biological and physical processes on a global basis every one to two days. A primary objective of the MODIS projects is to help scientists understand the Earth as a system. Measurements of clouds and aerosols in the atmosphere, sea surface temperature and chlorophyll in the oceans, land cover changes, and surface temperature and vegetation properties on the land will contribute to our understanding of the interactions between land, ocean, and atmospheric processes. By doing this, it is hoped that the scientific community can develop the capability to predict future change and to differentiate between the impact of human and natural activities on the environment. To accomplish this objective, MODIS acquires data in 36 bands distributed across the visible to thermal infrared regions of the electromagnetic spectrum with spatial resolutions, depending on band, of 250 m (820 ft), 500 m (1,640 ft) or 1 km (.62 mi) at nadir. The primary uses of the 36 bands are:

• Land/cloud boundaries
• Land/cloud properties
• Ocean color/phytoplankton/biogeochemistry
• Atmospheric water vapor
• Surface/cloud temperature
• Atmospheric temperature
• Cirrus clouds/water vapor
• Ozone
• Surface/cloud temperature
• Cloud top altitude

The MODIS receiving station is located on the roof of the International Arctic Research Center (IARC) at the University of Alaska Fairbanks.

For comprehensive information on the Terra and Aqua projects, please go to: http://terra.nasa.gov and http://aqua.nasa.gov

For information on NASA's Earth Observing System, please go to: http://eospso.gsfc.nasa.gov