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Cloud changes may lower global temperature

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Feb 22,2012

Research from The University of Auckland on changes in cloud height in the decade to 2010 has provided the first hint of a cooling mechanism that may be in play in the Earth’s climate.

Published in the journal Geophysical Research Letters, the analysis of the first ten years of data from the NASA Terra satellite revealed an overall trend of decreasing cloud height. Global average cloud height declined by around 1 per cent over the decade, or around 30 to 40 metres. Most of the reduction was due to fewer clouds occurring at very high altitudes.

“This is the first time we have been able to accurately measure changes in global cloud height and, while the record is too short to be definitive, it provides just a hint that something quite important might be going on,” explains lead researcher Professor Roger Davies. Longer-term monitoring will be required to determine the significance of the observation for global temperatures.

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"The Terra satellite is scheduled to continue gathering data through the remainder of this decade. “If cloud heights come back up in the next ten years we would conclude that they are not slowing climate change,” says Professor Davies. “But if they keep coming down it will be very significant. We look forward to the extension of this climate record with great interest.”

Professor Davies holds the Buckley Glavish Chair in Climate Physics at The University of Auckland. The current research was funded by NASA’s Jet Propulsion Laboratory, which is managed for NASA by the California Institute of Technology."

http://www.auckland.ac.nz/uoa/home/news/template/news_item.jsp?cid=466683

Cloud height decreasing on Earth and NASA scientists are unsure why

1-enasasatelli.jpg

images?q=tbn:ANd9GcTxuNvPkXhmolX9cbyPNg-IcE4I4bfSWN9z6VjtpWXs-o-FsjLUwg

"EARTH - Earth’s clouds got a little lower — about one percent on average — during the first decade of this century, finds a new NASA-funded university study based on NASA satellite data. The results have potential implications for future global climate. Data from NASA’s MISR instrument on NASA’s "

"Terra spacecraft show that global average cloud height declined by about 1 percent over the decade from 2000 to 2010, or around 100 to 130 feet (30 to 40 meters). Lead researcher Roger Davies said that while the record is too short to be definitive, it provides a hint that something quite important might be going on. Longer-term monitoring will be required to determine the significance of the observation for global temperatures."

"A consistent reduction in cloud height would allow Earth to cool to space more efficiently, reducing the surface temperature of the planet and potentially slowing the effects of global warming. This may represent a “negative feedback” mechanism – a change caused by global warming that works to counteract it. “We don’t know exactly what causes the cloud heights to lower,” says Davies. “But it must be due to a change in the circulation patterns that give rise to cloud formation at high altitude.” NASA’s Terra spacecraft is scheduled to continue gathering data through the remainder of this decade. Scientists will continue to monitor the MISR data closely to see if this trend continues."

"The timing of the decline in the planet’s cloud height also curiously corresponds to a mysterious period of acceleration of the migration of the magnetic north pole towards Siberia as the chart shows on the left. Might the two events be related?"

http://theextinctionprotocol.wordpress.com/

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ENASA satellite finds Earth's clouds are getting lower

enasasatelli.jpgphysorg.com

This image of clouds over the southern Indian Ocean was acquired on July 23, 2007 by one of the backward (northward)-viewing cameras of the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's polar-orbiting Terra spacecraft. Credit: NASA/JPL-Caltech

(PhysOrg.com) -- Earth's clouds got a little lower -- about one percent on average -- during the first decade of this century, finds a new NASA-funded university study based on NASA satellite data. The results have potential implications for future global climate.

2-enasasatelli.jpg[hysorg.com

Patterns that relate changes in cloud-top height with El Niño/ La Niña indicators. Image credit: University of Auckland/NASA JPL-Caltech

"MISR, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is one of five instruments on NASA's Terra spacecraft, launched in December 1999. The instrument uses nine cameras at different angles to produce a stereo image of clouds around the globe, allowing measurement of their altitude and movement. "

read more at.

http://www.physorg.com/news/2012-02-enasa-satellite-earth-clouds.html

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Noctilucent Clouds Get an Early Start

June 7, 2013

"June 7, 2013:  Every summer, something strange and wonderful happens high above the north pole.  Ice crystals begin to cling to the smoky remains of meteors, forming electric-blue clouds with tendrils that ripple hypnotically against the sunset sky.  Noctilucent clouds—a.k.a. "NLCs"--are a delight for high-latitude sky watchers, and around the Arctic Circle their season of visibility is always eagerly anticipated.

News flash: This year, NLCs are getting an early start. NASA's AIM spacecraft, which is orbiting Earth on a mission to study noctilucent clouds, started seeing them on May 13th.

"The 2013 season is remarkable because it started in the northern hemisphere a week earlier than any other season that AIM has observed," reports Cora Randall of the Laboratory for Atmospheric and Space Physics at the University of Colorado. "This is quite possibly earlier than ever before."

The early start is extra-puzzling because of the solar cycle.  Researchers have long known that NLCs tend to peak during solar minimum and bottom-out during solar maximum—a fairly strong anti-correlation.  "If anything, we would have expected a later start this year because the solar cycle is near its maximum," Randall says. "So much for expectations."

For sky watchers, this means it's time to pay attention to the sunset sky, where NLCs are most often seen.  An early start could herald brighter clouds and wider visibility than ever before.

February Fireballs (signup)Noctilucent clouds were first noticed in the mid-19th century after the eruption of super-volcano Krakatoa. Volcanic ash spread through the atmosphere, painting vivid sunsets that mesmerized observers all around the world.  That was when the NLCs appeared. At first people thought they must be some side-effect of the volcano, but long after Krakatoa's ash settled the noctilucent clouds remained.

ScienceCasts: An Early Start for Noctilucent Clouds

ScienceATNASA

"Glowing electric-blue at the edge of space, noctilucent clouds have surprised researchers by appearing early this year. The unexpected apparition hints at a change in the "teleconnections" of Earth's atmosphere."

Glowing electric-blue  Cherenkov radiation?

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