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Meteosat-8 TruColor Imagery:
Background:
This product is created by combining the 0.6, 0.8, 1.6, and 3.9µm
channels on the Meteosat-8 satellite. The 0.6, 0.8, and 1.6µm channels are
used as a proxy for the blue, green, and red regions of the visible spectrum and
are combined into a single image.
Uses:
The resulting merged "color" image closely mimics what an actual color photo of the
Earth would look like from space. These channels can only be used during the day,
so an algorithm is used to track the position of the solar terminator (sunset/sunrise
line) in each image. For portions of the image that are dark, the 3.9µm
shortwave infrared channel is used.
This imagery is useful for monitoring the position of aerosols (e.g. suspended
mineral dust in the Saharan Air Layer). Animations of the imagery are useful for
tracking suspended mineral dust and can also help identify the source of the dusty
air that is indicated in the imagery.
Notes:
• The visible portion of the TruColor image is subject to sun glint (solar
reflectance off the ocean surface). This effect can make it look "dusty", when
in fact, it may not be. This area of sun glint is easily identifiable as it
rapidly moves across the basin in successive images.
• Low sun angles (relative to the position of the satellite) can make it easier
to see suspended mineral dust because scattering by the aerosols is greater.
• Saharan mineral dust can often be seen as far west as the Windward Islands
(far western edge of the picture) in this imagery and looks like a brown haze.
• Cold clouds appear to have a bluish tint in this imagery. This is because
the three visible channels being used to create the TruColor imagery are only
proxies for the blue, green, and red portions of the visible spectrum.
For more SAL information, please visit the
SAL Background Information
page.
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