noctilucent clouds signs of an ice age?

Noctilucent clouds (NLC) are generally seen for a few weeks either side of the summer solstice primarily at latitudes between 50 and 60 degrees when the sun is between 6 and 16 degrees below the horizon, this corresponding to the midnight hours. Under these conditions the NLC are sufficiently high to still be illuminated directly by sunlight

userweb.elec.gla.ac.uk...

The clouds were first observed above polar regions in 1885 - suggesting they may have been caused by the eruption of Krakatoa two years before. But they have spread to latitudes as low as 40° in recent years. "They're also getting brighter, and each year there are more of them than in the previous year,"

www.newscientist.com...



a very quiet sun

back-scattering of sunlight by ice grains in the mesophere

According to Mie theory back-scattering of sunlight due to NLC spherical particles in the mesosphere, cool the sunlit planetary hemisphere of Earth.

Sunlight back-scattered from such particles is lost and is unavailable for the heating of the Earth.

Climatology of noctilucent cloud radii and occurrence frequency using SCIAMACHY
SCIAMACHY observes an increase of mean NLC particle size during the last 5 years at latitudes higher than 70, which might be linked to the decrease in solar activity.

Solar physicist Dean Pesnell of the Goddard Space Flight Center says "We're experiencing a very deep solar minimum,". "This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center

science.nasa.gov...



Increasing range of Noctilucent clouds, the first signs of an approaching ice age.

NLCs INVADE THE USA:
On July 15th, a wave of intense noctilucent clouds (NLCs) descended over the continental United States. "They were so bright, I would have assumed the dawn was imminent, only it was an hour and a half before sunrise!" The latitude of the Colorado sighting is only 39° N



[edit on 17-7-2009 by meaguire]