Geeks Champion New Armageddon-Worthy Cloud

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Geeks Champion New Armageddon-Worthy Cloud

Postby Sisyphus on October 11th, 2009, 12:23 pm 

Mike Olson wrote:In hill country from Iowa to the Scottish Highlands, sky-gazers have reported some strange, ominous-looking clouds of late. Dubbed undulatus asperatus (turbulent undulation), the atmospheric anomaly could be headed where only 80-odd clouds have gone before: into the International Cloud Atlas. If it makes the cut, asperatus will be the first new addition in more than 50 years.

Source: ... /st_clouds

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Re: Geeks Champion New Armageddon-Worthy Cloud

Postby DrCloud on October 11th, 2009, 12:50 pm 

In the lower atmosphere -- the part with the weather in it -- there are layers, especially near the ground. Turbulence induced by surface-related processes creates a turbulent boundary layer, which, if it gets deep enough, can reach to the condensation level. There (where the flat bases of little cotton-ball cumulus clouds occur), a second layer (the cloud layer) can form. Each of these is slightly stable with respect to the one below it. In a manner that's quite similar to waves on the surface of a body of water, waves can occur at the interface between the layers.

So, if there's enough available moisture, the cloud layer can pretty much fill up with condensed water -- cloud droplets. And if there are sources of turbulence on relatively large scales (bigger than surface-related processes that create the boundary layer) such as topographic features, the normally uniform condensation level can undulate with the waves.

That's consistent with the remarks in that little article, and it's what causes more common types of clouds, such as the lenticular clouds that occur in the lee of mountain ranges. HPH

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