From San Francisco, at a meeting of the American Geophysical Union
Studies of the contrails generated by jets flying high over Alaska may lead to improved techniques for predicting the formation of these artificial clouds, which some scientists suggest have a warming effect on Earth's climate.
The skies over Fairbanks, Alaska, are busy because the city lies beneath air routes between North America and the Far East, as well as the flight paths between nearby Anchorage and cities in Europe. Between March 2000 and July 2002, more than 2,500 jets passed within 80 kilometers of Fairbanks International Airport, says Martha Shulski, an atmospheric scientist at the University of Alaska in Fairbanks.
Of those aircraft, about 10 percent flew past during daylight hours with good visibility and within 4 hours of when weather instruments were lofted from the airport. The scientists observed contrails in 223 instances, and the clouds' lifespans varied from a few second