Recent Growth Of Noctilucent Clouds May Signal Near-Earth Warming, Mesosphere Cooilng - AFP

[hatrack]

EDIT

Noctilucent clouds form under conditions that counter common logic. They only form in the summer, when solar radiation is most intense, Collins said. That solar heating, rather than warming the mesopause, causes cooling, he said. "The mesopause region is colder in summer under perpetual daylight than it is in winter under perpetual darkness."

The reason lies in the movement of air within the atmosphere, Collins said. Solar radiation heats the lower atmosphere, causing a rising cell of air over the summer pole, he said. "As the air rises it cools and that beats out the radiative heating." Those cold temperatures allow the ice clouds to form in the mesopause. The clouds could serve as an indicator of climate change because an increase in carbon dioxide, which causes heating in the lower atmosphere, causes cooling in the upper atmosphere.

Collins said the noctilucent clouds are a relatively new phenomenon. History indicates that humans first recorded their presence in the 19th century, he said. Satellite and ground-based data has been limited, he said, but it appears that the clouds have become more prevalent over time.

A new satellite, Aeronomy of Ice in the Mesosphere, or AIM, was launched in April 2007 to observe clouds and their environment in the mesopause, Collins said scientists are looking forward to having more reliable data, which could contribute to a broader understanding of the upper atmosphere, noctilucent clouds and how both fit into the climate system.

EDIT

http://www.terradaily.com/reports/Polar_Ice_Clouds_May_Be_Climate_Change_Symptom_999.html

[Whoa_Nelly]

1. Have read about this before

It is very interesting.

(psst...you may want to edit and change wraming to warming ;) )

[hatrack]

2. Thanks for the spillign aisstence!

:toast:

[jwirr]

3. Dumb me, I do not understand the implications for us?

[phantom power]

4. it is additional evidence of greenhouse warming...

the greenhouse effect is keeping heat trapped near the surface. An interesting side-effect is that the upper atmosphere is cooling.

I suppose there will be some actual consequences of increasing temperature gradient between lower and upper atmosphere. But I don't know what they are. I guess an increase in noctilucent clouds is one.

[jwirr]

5. Thank you.