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Meteosat-8 Split Window:
Background:
This imagery is created by differencing the 12.0 and 10.8µm infrared
channels on the Meteosat-8 satellite. The algorithm is sensitive to the presence
of dry and/or dusty air in the lower atmosphere (~600-850 hPa or ~4,500-1,500 m)
and is denoted by the yellow to red shading.
Uses:
This imagery is useful for monitoring the position and movement of dry air
masses such as the Saharan Air Layer (SAL). Animations of the imagery are useful
for tracking these features and can also help identify the source of the dry and/or
dusty air that is indicated in the imagery.
Notes:
• Dry air and suspended aerosols (e.g. mineral dust) both contribute to a positive
"SAL" signal in this imagery, but the relative contribution of each cannot be
determined from this imagery alone.
• Polar air originating from the mid-latitudes produces a positive signal in this
imagery that is similar to that of the SAL. This is because both air masses contain
substantial dry air in the lower to middle troposphere. The JAVA movie is a useful
tool for determining which type of air mass is being indicated in the imagery.
For more SAL information, please visit the
SAL Background Information
page.
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