* Astronomy

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RE: AIM Satellite

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A Hampton University professor is pulling back the curtain on mysterious night-shining clouds that materialise only above Earth's poles, at the very edge of the atmosphere and space.
Jim Russell, lead scientist for the NASA-financed AIM satellite, has sifted through the first summer's worth of data on the wispy clouds. The satellite is the first to exclusively study these "noctilucent" clouds which means they reflect light and shine at night and Russell has found that they undergo more change, more rapidly, than suspected.
The clouds get brighter and stretch farther as the uppermost atmosphere gets colder. Russell thinks that those changes might be an effect of man-made climate change.

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Noctilucent Clouds

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Clouds that Rival Auroras Now Bigger and Brighter
Are bigger, brighter "night shining" clouds a symptom of climate change? NASA's AIM mission aims to find out.
Noctilucent clouds are made of ice particles 20 to 100 nanometers in size that float in the mesosphere well above normal clouds (the highest of which are 7 miles up) as well as the ozone layer (at 9 to 22 miles), but below the auroras (60 miles and higher). Although the air there is 100,000 times dryer than the Sahara's desert winds, extremely low temperatures around 143 degrees Celsius crystallise what little moisture there is on tiny dust particles that act as cloud seeds. In an interesting and so far unexplained atmospheric riddle, the air at that altitude is actually colder in summer than in winter, causing these clouds to form only in the summer months in either hemisphere.

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NASA Satellite Captures First View of 'Night-Shining Clouds'

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Image above: This image shows one of the first ground sightings of noctilucent clouds in the 2007 season. Credit: Veres Viktor of Budapest, Hungary taken on June 15, 2007.

The first observations of these "night-shining" clouds by a satellite named "AIM" which means Aeronomy of Ice in the Mesosphere, occurred above 70 degrees north latitude on May 25. People on the ground began seeing the clouds on June 6 over Northern Europe. AIM is the first satellite mission dedicated to the study of these unusual clouds.

These mystifying clouds are called Polar Mesospheric Clouds, or PMCs, when they are viewed from space and referred to as "night-shining" clouds or Noctilucent Clouds, when viewed by observers on Earth. The clouds form in an upper layer of the Earths atmosphere called the mesosphere during the Northern Hemispheres summer season which began in mid-May and extends through the end of August and are being seen by AIMs instruments more frequently as the season progresses. They are also seen in the high latitudes during the summer months in the Southern Hemisphere.

This image shows some of the first data returned from AIM, documenting noctilucent clouds located over the Arctic.

On June 11, 2007 the cameras on the AIM satellite returned some of the first data documenting noctilucent clouds over the Arctic regions of Europe and North America. This new data reveals the global extent and structure of these mysterious clouds, to a degree that was previously unattainable. White and light blue represent noctilucent cloud structures. Black indicates areas where no data is available. Credit: Cloud Imaging and Particle Size Experiment data processing team at the University of Colorado Laboratory for Atmospheric and Space Physics

Very little is known about how these clouds form over the poles, why they are being seen more frequently and at lower latitudes than ever before, or why they have been growing brighter. AIM will observe two complete cloud seasons over both poles, documenting an entire life cycle of the shiny clouds for the first time.

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The NASA the Aeronomy of Ice in the Mesosphere (AIM) satellite has observed the first occurrence this year of noctilucent clouds that form 50 miles above Earth.

The AIM satellite which is the first dedicated to the study of such cloud systems called Polar Mesospheric Clouds observed the high altitude clouds on May 25.
Often termed "night-shining" clouds when viewed from space -- or noctilucent when viewed from Earth -- the clouds form during the Northern Hemisphere's warmer seasons. They are also visible in the high latitudes of the Southern Hemisphere during those summer months.

"It is clear that PMCs are changing ... and we do not understand how, why or what it means. These observations suggest a connection with global change in the lower atmosphere and could represent an early warning that our Earth's environment is being altered" - James Russell III, AIM principal investigator, Hampton University.

Very little is known about how the clouds form, why they are being seen more frequently and at lower latitudes than ever before, or why they have been growing brighter.

Source UPI

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The US space agency (Nasa) has launched a mission to study the highest clouds on Earth - noctilucent clouds.
These silvery-blue structures appear as thin bands in twilight skies, forming some 80km above the surface.
Recent records suggest they have become brighter, more frequent and are being seen at lower latitudes than usual.
The Aeronomy of Ice in the Mesosphere (AIM) spacecraft was launched at 13:26 PDT (20:26 GMT) on Wednesday on a Pegasus XL rocket.

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A piano-sized NASA satellite was launched Wednesday on a mission that, astronomers hope, will reveal the unsolved mysteries of Earths highest clouds.
The Orbital Sciences-built Aeronomy of Ice in the Mesosphere (AIM) spacecraft is on a two-year mission to scan noctilucent, or night-shining, clouds that can only observed after sunset. An air-launched Pegasus XL booster rocketed skyward from California's Vandenberg Air Force base shortly before 4:23 p.m. EDT.

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The Aeronomy of Ice in the Mesosphere (AIM) mission, slated for launch on 25 April, will be the first mission dedicated to these clouds. Scientists are looking to gather the most basic information about how they form, including any hints as to whether their appearance could be linked to climate change.
First spotted two years after the 1883 eruption of Indonesia's Krakatoa volcano, noctilucent, or 'night-shining', clouds have been showing up more and more often over the years. They are now spotted more frequently, for longer periods of time, and at lower latitudes than ever before, says Jim Russell, an atmospheric physicist at Hampton University in Virginia.
Just why this is remains a mystery. Over the past three decades, several satellites have looked at noctilucent clouds, but never before has there been a mission dedicated to studying them.

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NASA's Aeronomy of Ice in the Mesosphere (AIM) spacecraft, the first mission dedicated to the exploration of mysterious ice clouds that dot the edge of space in Earth's polar regions, successfully launched from Vandenberg Air Force Base, Calif., at 1:26 p.m. PDT on Wednesday, April 25.
The mission will study clouds that are noctilucent, meaning they can be seen from the ground only at night, when they are illuminated by sunlight no longer visible from the Earth's surface.

"The successful AIM launch initiates an exciting new era in understanding how noctilucent clouds form and why they vary. The coordinated AIM measurements will provide the first focused and comprehensive data set needed to unravel the mysteries of these clouds" - Principal Investigator James M. Russell, III, of Hampton University in Hampton, Va.

Noctilucent clouds are increasing in number, becoming brighter and are occurring at lower latitudes than ever before.

"Such variations suggest a connection with global change. If true, it means that human influences are affecting the entire atmosphere, not just the region near the Earth's surface" - James M. Russell

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