Hampton U. Data Shed New Light on Night Clouds

Associated Press
Wednesday, January 2, 2008

HAMPTON, Va. -- A Hampton University professor is shedding new light on night-shining clouds that might be affected by climate change. Jim Russell is the lead scientist for the NASA-funded AIM satellite, the first to study the wispy "noctilucent" clouds, which only appear above Earth's poles.

Russell, an atmospheric science professor at Hampton, has found that the clouds get brighter and stretch farther as the uppermost atmosphere gets colder. He thinks that the changes might be caused by human-generated global warming.

The Aeronomy of Ice in the Mesosphere satellite is providing the first global mapping of the cover and structure of these clouds, which coalesce as icy dust particles about 42 to 60 miles above the Earth's surface.

The mapping showed that the clouds are more sensitive to changes in the upper atmosphere than was previously thought, as they are changing in brightness and reach.

Scientists say that's why people as far south as Colorado and Utah have spotted the clouds in recent years.

Previously, they had only been visible to people in regions of northern Europe and Canada.

AIM is funded through NASA's Small Explorers program. It has a $140-million budget through May 2009, but Russell hopes to get funding to extend the research.

The satellite is now studying the clouds at the South Pole. Noctilucent clouds form only in the summer of the respective hemispheres, when, somewhat counter-intuitively, it is coldest at the highest reaches of the atmosphere.

"We want to look at long-term changes," said Russell, who presented his first batch of results at a recent meeting of the American Geophysical Union in San Francisco. "We have such great sensitivity that we really want to get a long-term database."

Russell said the connection to climate change may involve changes in temperature and water vapor.

As the Earth's surface-level climate warms up, the coldest region of the atmosphere, where these clouds exist, actually gets colder. The colder it gets, the farther the clouds reach.

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HU's AIM Mission Results Revealed
AIM Satellite Pictures Reveal Clouds are Brighter, Appearing more Frequently

Hampton, VA - Hampton University's Dr. James M. Russell, III, discussed initial results from The Aeronomy of Ice in the Mesosphere (AIM) satellite mission at the American Geophysical Union meeting held in San Francisco, Dec. 10-14.

Hampton University is the first Historically Black College and University (HBCU) to have complete mission responsibility of a NASA satellite mission. AIM, launched in April 2007, investigates noctilucent "night shining" clouds, which are also known as Polar Mesospheric Clouds (PMC). The mission is quantifying the life cycle of these clouds that form at very high altitudes in our atmosphere above about 50 miles where the temperatures during local summer are about minus 230 degrees Fahrenheit.

"The AIM mission has changed our view of PMCs after only one season of observations," stated Russell, AIM principal investigator and co-director of the HU Center for Atmospheric Sciences." The measurements show the brightest clouds ever observed, with more variability and structure than expected, signifying a greater sensitivity to the environment in which the clouds form. They also show that the clouds exist in a much broader altitude layer than was believed to be the case before AIM was launched."

Russell shared results from the satellite observations of the clouds during the 2007 Northern Hemisphere PMC season. The satellite detected the clouds from May 25 through Aug. 25. Russell found that the clouds appeared more frequently, were extremely variable, changed on a daily and hourly basis, and were observed at lower latitudes than previously measured. The AIM measurements are providing the most detailed understanding ever of these 'night-shining clouds.'

The AIM mission is now poised to make these unprecedented PMC measurements in the southern Hemisphere where temperatures are now cold enough for their formation.

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