Contrails and Aviation-induced Cirrus Clouds
Effects on quality and quantity of Sunlight (01)
So, what does all this have to do with satellite images?
You see a cloud because its constituents (water droplets) scatter and reflect
sunlight. So does the satellite. Clouds appear white because the
water droplets scatter all of the wavelengths in the visible part of the
What about the rest of the spectrum? Any UV that is scattered off the cloud tops would just make the image fuzzy, so the satellite optics filter the UV out. However, optics that sense infrared can "see" into the cloud.
The IR waves are so long that most of them miss the water droplets. That's what happens to the IR component of sunlight -- most of it just passes through the cloud. However, the droplets themselves are emitting IR radiation (just like the hot stove, except that the waves are less energetic and much longer). These waves also pass through the cloud, and the ones going upward are what the satellite sees.