High-altitude noctilucent clouds have been mysteriously spreading around the world in recent years (Image: NASA/JSC/ES and IA)
Posted on 05/30/2006 7:03:44 AM PDT by S0122017
Mysterious glowing clouds targeted by NASA 17:07 26 May 2006 NewScientist.com news service Maggie McKee Print this pageEmail to a friendRSS Feed
High-altitude noctilucent clouds have been mysteriously spreading around the world in recent years (Image: NASA/JSC/ES and IA)
AIM mission, Hampton University Noctilucent clouds, University of Colorado Scott Bailey, University of Alaska Glowing, silvery blue clouds that have been spreading around the world and brightening mysteriously in recent years will soon be studied in unprecedented detail by a NASA spacecraft.
The Aeronomy of Ice in the Mesosphere (AIM) mission will be the first satellite dedicated to studying this enigmatic phenomenon. Due to launch in late 2006, it should reveal whether the clouds are caused by global warming, as many scientists believe.
"Noctilucent" clouds, which glow at night, form in the upper atmosphere, at an altitude of about 80 kilometres, and their glow can be seen just after sunset or just before sunrise.
"Even though the Sun's gone down and you're in darkness, the clouds are so high up, the Sun is still illuminating them," explains AIM principal investigator James Russell at Hampton University in Virginia, US. Russell described the mission on Thursday at a meeting of the American Geophysical Union in Baltimore, Maryland, US.
Bigger and brighter 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," Russell told New Scientist.
Many researchers believe this proliferation is down to human activities. "You need three things for clouds to form: particles that water can condense onto; water; and cold temperatures," says Russell. He says pollution and global warming are thought to be responsible for two of those factors.
Atmospheric water may be boosted by livestock farming and the burning of fossil fuels, which spew methane into the atmosphere: sunlight breaks down the methane, releasing hydrogen that can bond with oxygen to form water.
And greenhouse gases such as carbon dioxide actually help to cool the upper atmosphere, where the clouds form. That is because the atmospheric density is so low at that altitude that the gases cannot trap heat as they do closer to the Earth's surface, and the heat is simply radiated into space.
Alien ice As yet, it is not clear what the source of the particles that "seed" the clouds is. The clouds form during the local summer months, when the pole is bathed in perpetual sunlight. So one possibility is that warm air rising above the pole could carry dust upwards from lower atmospheric altitudes, onto which water can condense.
But the dust could also have a cosmic source, dropping into the atmosphere from space. "It may be there's a constant supply of particles but a changing temperature and water environment makes the conditions right to grow ice particles," says Russell.
AIM will use three instruments to study the clouds. One is a suite of four cameras that will provide panoramic views of the poles and clouds. Another, called the Solar Occultation for Ice Experiment (SOFIE), will study the chemistry of the ice particles and clouds – measuring molecules such as methane. It will also observe the Sun through the atmosphere to measure how much sunlight is dimmed by dust in the atmosphere.
The third instrument, called the Cosmic Dust Experiment, is a plastic film that sits on top of the spacecraft. It will record every "hit" from a dust particle that rains down on it from space.
Cloud umbrella "We want to know why the clouds form and why they vary," says Russell. "If there is a human connection, it'll tell us that we're doing something to the atmosphere and that we need to determine what the long-term consequences are."
Some scientists speculate that the clouds might actually help mitigate global warming, says Russell. "If these clouds were to continue to grow and cover broad areas of Earth, they would form something like a thin, semi-transparent umbrella," he told New Scientist. "They would reduce the amount of solar rays making it to the ground, so they could actually reduce the effects of global warming."
The AIM satellite will launch into a polar orbit from California's Vandenburg Air Force Base. Russell says it may lift off in December, but its exact launch date has not been set because mission planners are still working to minimise vibration forces on the spacecraft due to its Pegasus XL launch rocket.
ping noctilucent clouds
It's a shame that the cold temps required for the clouds are not associated iwth global warming. Oh wait, the nut case "scientists" claim that cold temps are also caused by global warming. It's amazing how they make GW fit every case.
EVERYTHING is caused by globals warming!!
Scientists... they sure know everything don't they.
Beautiful day for a mow
If you are to believe the global warming fear mongers, "many scientists" believe that human caused global warming is responsible for everything from herpes to locust swarms. Any article with a statement such as this is not worth reading. Consensus is not science.
I think that was the idea. Except that they continue to expand even when no volcanoes where active.
I think they would look pretty neat, and if they also may slow global warming down than I don't see any harm of those clouds.
Huh???????
Yes... global warming was the first thing that I thought of also!
Man, are these people obsessed!
Good catch in post 10.
Methane is a fossil fuel called natural gas. Burning it releases co2 and water.
Cow farts?
Chem TRAILS! RUN FOR YOUR LIVES!............
This will add to the many factors scientist ignore in their global warming models. The reason their models show global warming spinning out of control is the 'scientists' relunctance to add in factors that mitigate global warming. In fact their highend estimate intentially took out all mitigating factors so they could get a high number to scare people with. It is one thing to do that for fun, but to publish that number as the highend prediction is intellectually dishonest. Science is just politics anymore. Science is in a sad sad sad state.
Another article on global warming today?
This is the 'news story du jour', I guess cuz of AlGore's movie.
Someone needs to get kidnapped in Aruba, or maybe we can get Brad and Angelina to adopt a few more kids from somewhere. Quick, get me Geraldo on the phone, stat!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.