Contacts:

BOULDER--NASA and an international science and education outreach program called GLOBE are conducting a worldwide experiment on Earth Day, April 22, 2004 in celebration of the GLOBE program's tenth anniversary. Everyone interested in helping develop a better understanding of Earth is invited to join. GLOBE is based at the University Corporation for Atmospheric Research (UCAR) in Boulder, Colorado.

Participants will observe contrails and report their findings to scientists. Contrails are clouds formed from water vapor in aircraft exhaust. Observations will be tallied and reported state by state and country by country to illuminate any patterns of contrail activity.

"Contrails are one change in Earth's system that are without a doubt caused by human activity, so it is appropriate that on Earth Day we assess how people are impacting the state of our planet," said Lin Chambers, director of the Contrail Education project, in partnership with GLOBE, at NASA Langley Research Center, Hampton, Virginia.

Contrails represent a human-caused increase in the Earth's cloudiness and impact the atmosphere and climate. Observations by people in the United States and around the globe may help scientists better understand under what atmospheric conditions contrails form.

"We thought spotting contrails would be a fun and educational activity that could include more schools and the general public since no instruments are required," said Peggy LeMone, GLOBE chief scientist at UCAR. "The distribution of sightings tells us both where jets are flying and where weather conditions favor contrails forming. We can also compare the contrail patterns to satellite images."

The observation experiment, called the Earth Day 2004 Contrail Count-a-Thon, is an opportunity to become involved in a hands- on, real-world science experiment. For this activity, GLOBE and NASA are encouraging the public around the world, including students and non-students alike, to participate.

If no contrails are visible, then participants may observe other clouds or clear skies and report their findings. Participants in the Earth Day 2004 Contrail Count-a-Thon do not have to be members of GLOBE outreach projects. Current GLOBE members should follow their normal instructions for reporting observations on April 22.

GLOBE was founded on Earth Day 1994. Since then, over a million primary and secondary students in more than 14,000 schools worldwide have taken part in the program. As of October 2003, students had reported over 10 million scientific measurements using protocols developed by scientists in a variety of scientific areas including atmosphere, climate, soils, hydrology, land cover, biology, and phenology.

GLOBE brings together students, teachers, and scientists to support improved student achievement in science, technology, engineering, and mathematics and to gather important data for the global Earth science community.

NASA works with GLOBE to help achieve its mission of inspiring the next generation of explorers. GLOBE is an international student observation campaign managed as a partnership between UCAR and Colorado State University under a cooperative agreement with NASA, with sponsorship by the National Science Foundation and the U.S. Department of State.