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Credit: E. Wiebe

Fog seen on Mt. Tolmie in Greater Victoria, British Columbia. Tiny water droplets make up this cloud. They are of the order of 1 to 10 micrometres which is a least ten times smaller than the human eye can easily discern. So, individually invisible, the water drops do become visible on mass because of their effect on light. Through a process called Mie Scattering visible light, which has wavelengths about ten to one hundred times smaller than the water droplets, is scattered in all directions leading the fog to appear white and preventing us from seeing too far into it. Some light is also absorbed by the droplets. So, light entering the cloud of fog bounces around in all directions and appears to be emitted from the cloud itself. We lose all ability to see any detail in this amorphous glow and distinctive landmarks become invisible in the distance. Rather than not seeing the forest for the trees, we can't see the trees at all, only the forest.

Here's another foggy scene familiar to everyone living near Canada's Pacific coast.




UVic / SEOS / Climate Group / About Front Page Picture / Fog in Victoria, BC Last updated: Thursday, 31-Jan-2013 14:02:04 PST
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