Water Vapor Imagery
Water vapor satellite imagery is derived from radiation emitted by water vapor at wavelengths
which are not in an atmospheric window: 6 to 7 µm.
If the upper troposphere is moist, radiation reaching the satellite will originate from this
(cold) region and be displayed in light or nearly white shades.
If the upper troposphere is dry, radiation will originate from water vapor at warmer levels
and be displayed in darker shades.