Snow stretches from the English Channel north under a bank of clouds near the Scottish border in this photo-like image of England, taken on February 4, 2009.
Acquired February 21, 2010, these true- and false-color images of British Columbia show fog filling mountain valleys northeast of Vancouver. In the false-color image, vegetation appears bright green, snow appears bright turquoise, and fog appears as a very pale, muted blue-green.
In a photo-like satellite image, the faintest of shadows or shading of grey may give them away, but more often, clouds over the poles simply disappear against the background, camouflaged from the satellite’s view by the underlying snow and sea ice. For those trying to track clouds from space, to understand cloud physics, say, or to predict the weather, the problem is frustrating. Only with a combination of visible and invisible wavelengths of light, such as infrared light, do clouds become distinct from the snow and ice below.