Clouds

One of the most interesting things I saw when I first came here were the clouds. Never before I've seen them so close. I almost felt I could touch them. I remember driving over Snoqualmie Pass on my way to Eastern Washington and the clouds were so low I was actually driving through them when I got high enough. I still find it beautiful when I see white clouds in blue skies.

I remember from my early school days that you can tell a lot from the color or the cloud. If the cloud is dark, it means it is thick, but a thin cloud will let much more light through and as a result will be much lighter. I found on Wikipedia that a green color may indicate heavy rain, hail, strong winds and possible tornadoes. Yellowish clouds may signal forest fire season due to the presence of pollutants in the smoke. Yellowish clouds are sometimes seen in urban areas with high air pollution levels.

Clouds also participate in regulating weather and climate but the complexity of how they are being created cases uncertainty in projections of global warming. On the one hand, white colored clouds promote cooling of the Earth by reflecting radiation from the Sun. However radiation that makes it to the ground is reflected back and easily absorbed by water in the clouds resulting in a net warming at surface level. (I took this phrase almost entirely from Wikipedia)

Another interesting new research relevant to the clouds, indicates a global brightening trend.[*] I found it interesting that there is a cyclical brightening and dimming in the skies as time goes by that is relevant to climate changes.

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*Martin Wild, Hans Gilgen, Andreas Roesch, Atsumu Ohmura, Charles N. Long, Ellsworth G. Dutton, Bruce Forgan, Ain Kallis, Viivi Russak, and Anatoly Tsvetkov. From dimming to brightening: Decadal changes in solar radiation at Earth’s surface. Science, 308(5723):847–850, 5 2005. URL http://www.sciencemag.org/cgi/content/abstract/308/5723/847.