M   [MODIS in Clean Room]
O  
D MODerate-resolution
I Imaging
S Spectroradiometer

MODIS will view the entire surface of the Earth every 1-2 days, making observations in 36 co-registered spectral bands, at moderate resolution (0.25 - 1 km), of land and ocean surface temperature, primary productivity, land surface cover, clouds, aerosols, water vapor, temperature profiles, and fires.

MODIS is a whisk broom scanning imaging radiometer consisting of a cross-track scan mirror, collecting optics, and a set of linear arrays with spectral interference filters located in four focal planes. MODIS has a viewing swath width of 2330 km (the field of view sweeps ± 55¡ cross-track) and will provide high-radiometric resolution images of daylight-reflected solar radiation and day/night thermal emissions over all regions of the globe. Its spatial resolution ranges from 250 m to 1 km at nadir, and the broad spectral coverage of the instrument (0.4 - 14.4 µm) is divided into 36 bands of various bandwidths optimized for imaging specific surface and atmospheric features. The observational requirements also lead to a need for very high radiometric sensitivity, precise spectral band and geometric registration, and high calibration accuracy and precision.

The MODIS instrument has one of the most comprehensive onboard calibration subsystems ever flown on a remote sensing instrument. This onboard calibration hardware includes a solar diffuser, a solar diffuser stability monitor, a spectroradiometric calibration assembly, a plate-type black body, and a space viewport.

MODIS operates continuously during the day and night portions of each orbit. In normal science mode, data from all bands are collected during the day portion of an orbit, whereas only the thermal infrared band data are collected during the night portion of an orbit. The instrument is calibrated periodically using the three internal targets—solar diffuser, blackbody, and spectroradiometric calibration assembly.

MODIS is a facility instrument provided by NASA and managed by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. It was built by Hughes Corporation's Santa Barbara Remote Sensing (SBRS) in Santa Barbara, California. The MODIS Team Leader is Vincent V. Salomonson. For more details, refer to the MODIS Web Page at http://modis.gsfc.nasa.gov.

MODIS will measure:

  • surface temperature (land and ocean) and fire detection;
  • ocean color (sediment, phytoplankton);
  • global vegetation maps and change detection;
  • cloud characteristics;
  • aerosol concentrations and properties;
  • temperature and moisture soundings;
  • snow cover and characteristics; and
  • ocean currents.

MODIS Instrument Characteristics
Spectral range 0.4-14.4 µm
Spectral coverage ± 55°, 2330 km swath (contiguous scans at nadir at equator)
Spatial resolution 250 m (2 bands), 500 m (5 bands), 1000 m (29 bands) at nadir
Duty cycle100%
Data rate6.2 Mbps (avg), 10.8 Mbps (day), 2.5 Mbps (night)
Mass274 kg
Power162.5 W (avg for one orbit), 168.5 W (peak)

[NDVI Fire Potential] [Landsat Fire Scars] (a, left) Landsat Thematic Mapper (TM) false color image for a region around Choma, Zambia (WRS: 173/071, acquisition date July 27, 1992) with fire burn scars clearly identified as the large dark/black polygons (Jacqueline Kendall, Goddard Space Flight Center).
(b, right) Simulated MODIS 250 m data derived from the Landsat TM image described in figure (a). [MODIS Fire Scars]
This fire potential index was derived from weekly composites of AVHRR Normalized Difference Vegetation Index (NDVI) and surface temperature data obtained from NOAA-14 (processed and provided by EROS Data Center). The image shows regions in 11 of the midwestern United States that are moderately (orange) to highly (brown) susceptible to the outbreak of a wildfire due to dry conditions on the ground. There is low fire susceptibility in those regions colored light tan and green. Although this particular image product is still at the experimental stage, the Land Discipline Group plans to provide global fire susceptibility maps to the public once MODIS data become available (Ramakrishna Nemani, Lloyd Queen, Jim Plummer, and Steve Running, U. of Montana).

[AVIRIS Cloud Mask]
These images illustrate a planned application of MODIS' new 1.375 µm cirrus channel (using AVIRIS data): (a) image taken over an ocean-land interface region where the presence of thin clouds obstructs the view of the surface (0.65 µm band alone); (b) the same image using three bands (red - 0.65 µm, green - 0.86 µm, blue - 0.47 µm), uncorrected; (c) the same image (1.375 µm cirrus band alone), observing high clouds only due to the strong water vapor absorption in the lower troposphere in this band; (d) the same image as the one in (b) but corrected to provide an unobstructed view of the surface (Bo-Cai Gao, Naval Research Laboratory).

Return to Index Previous Page Next Page: MOPITT Next Section: EOSDIS