NOAA CoastWatch produces near real-time true color satellite images
for U.S. coastal regions
from the Visible Infrared Imaging Radiometer Suite (VIIRS)
on-board the polar-orbiting Suomi-NPP satellite.
True color satellite images are like a camera photo.
The instrument's visible measurements at the red, green, and blue
wavelengths are combined to create a color-realistic image, just
like a digital photograph.
Land and water features can be seen in these images. Because cloud
coverage is very obvious, these images can be used to quickly determine
if a particular day's image is useful for observing a land or water feature.
NOAA/NESDIS processes the Sensor Data Record (SDR) calibrated
radiances for all wavelengths, and CoastWatch then generates data files
with the red, green and blue radiance measurements extracted for generating
true color images. Currently, CoastWatch true color data and image
files are available for the VIIRS instrument's 750 m
spatial resolution wavelength bands. The radiances are top-of-atmosphere
measurements and are not corrected for atmospheric effects,
such as a Rayleigh correction. In the future, CoastWatch anticipates
offering true color data and images at the much higher spatial resolution
of 375 m with Rayleigh atmospheric correction for U.S. coastal regions.