First Results: Update on AIM Satellite and Night-Shinning Clouds

The AIM satellite has returned the first ever satellite images of night-shinning clouds, as reported by Huliq:Breaking News and a NASA/Goddard Space Flight Center (NASA/GSFC) press release. The publicly available image is chilling.

A heavy covering of bright white clouds, surrounded by thinner electric blue clouds, spreads out from the North Pole on all sides, spanning the globe. The concentration of heavy white clouds is over the European hemisphere. The American hemisphere has a fine veil of blue clouds. These are noctilucent clouds. A black gap over the Pole is the area where AIM images are unavailable.

Clouds form because of a combination of particles (dust) and moisture. The water droplets grow around a cloud condensation nuclei (CCN) and when collected in sufficient quantity form a cloud. In the troposphere, this works out very well.

The mesosphere is the uppermost layer of Earth's atmosphere and stands at the edge of space. It is cold. It is dry. And it is particle free. Or rather it is believed that it was. It is not any longer, and it is the task of the AIM satellite to find out why, and to find what is now in the mesosphere. Because whatever it is, it is forming night-shinning clouds.

When studied or seen from space, as from AIM, which means Aeronomy of Ice in the Mesosphere, or as from the International Space Station (ISS), these iridescent night-shinning clouds are called Polar Mesospheric Clouds (PMCs), when viewed from earth they are Noctilucent Clouds (NLCs).

While AIM is returning valuable images of the global extent and variability of PMCs, the AIM instruments are also returning preliminary information on component particle sizes and shapes, as reported by Huliq. AIM has three state-of-the-art instruments that successfully began observations four weeks after the AIM launch on April 25.

The first instrument called the Cloud Imaging and Particle Size instrument provides a 2-D panoramic look at PMCs by collecting 360 degrees of multiple images. The second called the Solar Occultation For Ice Experiment measures data on cloud particles, specifically their variability according to altitude, the chemicals within the clouds, and the chemical in the environment in which the clouds form. The third called the Cosmic Dust Experiment records the amount of space dust entering Earth's atmosphere in order to assess whether space dust provides the foundation for the CCN, the cloud condensation nuclei, in the formation of PMCs.

The first data were received on June 11, according to NASA/GSFC. These early data indicate that PMCs form early in the spring season at high polar latitudes and travel down to lower latitudes--where they can be seen sweeping Europe and scattering over North America--as the spring and summer PMC season progresses. The Northern Hemisphere PMC season is mid-May to mid-August, the Southern Hemisphere PMC season is the southern spring and summer that falls between mid-November and mid-March.

AIM has a two year mission and so will measure PMCs at both poles for two complete cycles. However, the first early results from the AIM mission will be reported in Fairfax, Alaska in August 2007 at a major international conference that will focus on PMCs and other high altitude layered phenomenon, as reported by Huliq.

AIM captured the first PMC event of the season. Forming in the mesosphere, PMCs occurred at 70 degrees latitude, close around the North Pole, on May 25th. By July 6th, they had spread to to latitudes low enough to be seen over Northern Europe. As July progressed they had spread as far south as to be visible in France. Later, the thinner blue wisps had spread to lower latitudes over the Western hemisphere and were seen in Washington and Oregon. These displays were reported on Spaceweather.com and recorded in a viewer-submitted NLC photo gallery.

A powerful motivation behind the AIM mission can be seen in a statment, which is reported by Huliq and NASA/GSFC, made by principal AIM investigator of Hampton University in Hampton, Virginia, James Russell III: "It is clear that PMCs are changing, a sign that a distant and rarefied part of our atmosphere is being altered, 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."

The AIM science team will study these new data to understand whether these changes that Dr. Russell speaks of are related to global climate change.

Note as stated by Huliq: The AIM mission coincides with the two-year, worldwide scientific community's International Polar Year, and the mission is expected to make unique contributions to the International Polar Year's objective of advancing polar research.Huliq:Breaking News, "NASA satellite captures night-shining clouds." Huliq:Breaking News. URL: http://www.huliq.com/25974/nasa-satellite-captures-night-shining-clouds

Cynthia O'Carroll, Goddard Space Flight Center, "NASA Satellite Captures First View of 'Night-Shining Clouds'." NASA/Goddard Space Flight Center. URL: http://www.nasa.gov/mission_pages/aim/multimedia/first_view.html

AIM is the ninth Small Explorers mission under NASA's Explorer Program and is managed by the Explorers Program Office at the Goddard Space Flight Center, Greenbelt, Md. The AIM Project Data Center is located at Hampton University.-NASA/Goddard Space Flight Center.