| Shuttle astronauts are clearly fascinated by
the topside view of Earth's atmospheric patterns that space flight provides,
since every space shuttle crew takes a significant number of photographs
of clouds. In the past two years, interest in clouds has increased considerably
as scientists attempt to understand
global warming and the greenhouse effect. Efforts to predict climatic changes associated with global warming have focused new attention on the warming and cooling properties of clouds. The picture is a complex one, involving competing feedback mechanisms, and is not fully understood at this time. All clouds block some fraction of the incoming solar radiation, and absorb some fraction of the heat radiated back from the Earth's surface, and the balance between these two processes is hard to quantify. However, contemporary thinking suggests that the lower altitude cumulus clouds (such as pictures Thunderstorms, Brazil and Cumulus Cloud Tops) have a net cooling effect on Earth's surface, reflecting heat back to space. Conversely, the higher, thin cirrus clouds (such as pictures Jet Stream Cirrus and Jet Stream Cirrus, Saudi Arabia) trap heat, reflecting it back to the surface of Earth. |
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