True Color

Table describing some of the most widely used RGB products, with a sample image for the true color RGB

Description: True color is derived by combining three solar wavelengths, all in the vicinity of the wavelength of human vision. This makes for very realistic images, with colors that imitate how the human eye might see the scene. Currently (as of 2010), the MODIS imagers on board the EOS-Terra and Aqua satellites have the requisite visible channels to produce true color images and therefore provide a preview for what the upcoming VIIRS imager on the NPP satellite will be able to produce.

Coverage: Day only

Channels: Three solar wavelengths from MODIS

  • Blue (0.488-µm)
  • Green (0.555-µm)
  • Red (0.640-µm)

Color scheme:

  • Vegetated areas are green
  • Deserts are brown
  • Clouds are white
  • Water is blue

Advantages:

  • Produces a result comparable to color photography
  • Very easy to interpret
  • Particularly useful for viewing land surfaces for geological and land-use analysis
  • Provides compelling views of smoke and dust storms

Limitations:

  • Daytime only
  • No microphysical information for clouds
  • At present (2010), only produced by MODIS; an identical product will be available with VIIRS

Link: NRL NexSat site, http://www.nrlmry.navy.mil/NEXSAT.html

Reference: Miller, S. D.,Hawkins, J. D., Kent, J., Turk, F. J., Lee, T. F., Kuciauskas, A. P., Richardson, K., Wade, R., and Hoffman, C., 2006: NexSat: Previewing NPOESS/VIIRS Imagery Capabilities. Bulletin American Meteorological Society, 87, 433-446. http://www.nrlmry.navy.mil/NEXSAT.html

Examples:

MODIS True Color RGB over So. California in Oct 2007, shows smoke from fires

This MODIS true-color product shows southern California in October 2007. Coastal regions, which are often green, are as brown as the deserts. The smoke from fires (bluish white) and the dust (brownish white) have been blown offshore by fierce offshore winds.

MODIS True Color RGB over Nebraska, Kansas, and Oklahoma, 23 Aug 2009

This true color mage was produced during a relatively cool, wet summer over the Great Plains of the United States, with the green areas over Oklahoma, Kansas, and Nebraska representing dense crops. The 100th meridian traditionally marks a boundary, with greener, wetter conditions to the east, and browner, drier conditions to the west.