 |
|
|
|
Polar Ice Clouds May Be Climate Change SymptomScience Daily — As the late summer sun sets in the Arctic, bands of wispy, luminescent clouds shine against the deep blue of the northern sky.  Noctilucent clouds shine in the dark portion of the sky in this image taken from the Poker Flat Research Range in 2005. (Credit: Photo courtesy of Richard Collins, UAF Geophysical Institute) To the casual observer, they may simply be a curiosity, dismissed as the waning light of the midnight sun. But to scientists, these noctilucent ice clouds could be an upper-atmospheric symptom of a changing climate. “The question which everyone in Alaska is dealing with is what are the symptoms of climate change and, as in medicine, how do these symptoms reflect the underlying processes,” said Richard Collins, a researcher at the Geophysical Institute at the University of Alaska Fairbanks. “It is believed that [these clouds] are an indicator of climate change.” Dozens of scientists from several countries will gather at the University of Alaska Fairbanks Aug. 20-23 to discuss the latest findings on noctilucent clouds and other phenomena of the earth’s upper atmosphere during the Eighth International Workshop on Layered Phenomena in the Mesopause Region. Sessions will include information on the latest ground-based and satellite data on the mesopause region, an area of the atmosphere 50 miles above Earth’s surface and the site of the coldest atmospheric temperatures. 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. Note: This story has been adapted from a news release issued by University of Alaska Fairbanks. New! Search Science Daily or the entire web with Google: |
Science Video News
Two mathematicians at the University
of Northern Colorado are taking a fresh statistical look at the effects of
elevation on hitting -- specifically ... > watch video
Industrial toxicologists at a non-profit
venture founded by Procter & Gamble developed PUR, a water purifier
that combines a flocculant -- which ... > watch video
Ecological engineers have
developed software that can model the path of a toxic spill in waterways
anywhere in the United States. The system can ... > watch video
One hundred schools in 11 countries are
participating in a program to help NASA calibrate the measurements from
CloudSat, a remote-sensing satellite. ... > watch video
A NASA scientist, who died recently,
helped understand how the color of aerosols determines its role in cloud
formation. Light-colored aerosols -- ... > watch video
A new weather warning system can alert
airplane pilots when a thunderstorm is likely to form along their route
within the next hour. It uses ... > watch video
A new kind of waste digester uses two
different strains of bacteria in different tanks. This would normally take
place in the same environment, but ... > watch video
Electrical engineers have developed a system
that identifies a recycling bin by its household, using Radio Frequency
IDentification (RFID) chips ... > watch video
Satellite imaging is now helping
atmospheric scientists link the amount of charged ice in clouds to
lightning activity. Ice particles in ... > watch video
Computer, electrical, and
mechanical engineering students at the University of Florida have built a
fully automated underwater vehicle. Driven by ... > watch video
Bill Gray, the lead author
of closely-watched seasonal hurricane forecasts, is passing the torch to
his collaborator Phil Klotzbach, a man whose ... > watch video
Physical chemists have created a new, cheap
test to detect mercury, an element known to harm the brain, kidneys,
heart, lungs and immune system. A ... > watch video
Related News SectionsRelated News TopicsRelated Science StoriesRelated Encyclopedia ArticlesRelated Book Reviews |