NOAA CoastWatch East Coast Node
Data Types Info Data Types: SST         - AVHRR                 - GOES                 - Geo-Polar Blended                 - PODAAC MUR Chl-a       - MODIS Clarity     - K490                 - Rrs667 (MODIS)                 - Rrs672 (VIIRS)                 - TSM True Color (VIIRS)
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Region Info Regions: U.S. East Coast North East Coast Gulf of Maine Massachusetts & RI Bays Mid-Atlantic Coast NY-NJ Bight & Long Island Sound Chesapeake & Delaware Bays South East Coast Carolina Coast Florida - Georgia Coast

 

VIIRS True Color Satellite Images

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.


Apparent Stripes:
Because VIIRS pixels are aggregated toward the edge of the scan (to preserve pixel resolution as the instrument views along its scan line), gaps result when the aggregated pixel data are projected to a geographic grid. These gaps appear in a stripe-like formation and indicate the instrument's edge of scan. See example at the right: stripes on the image's right side.


Compositing Effects:
Several successive satellite orbits may pass over a given area. When daily composites are created, data from neighboring orbits may be included in a single image. If clouds have moved in the time between orbits, discontinuities may appear in the composited image. In addition, the different orbits will be viewing the area from different angles, resulting in composites that have a mixture of geometries and atmospheric effects. See example at the right.


Data Access


 
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