Jets' contrails contribute to heat-trapping high-level clouds
Condensation trails that airplanes produce mean not only a white-streaked sky on some days, but an increase in the amount of high-level clouds and, by extension, warming temperatures, according to a Penn State researcher. By comparing National Oceanic and Atmospheric Administration satellite images showing contrail occurrence with data from eastern U.S. stations that record sky-coverage for different levels in the atmosphere, Penn State Professor of Geography Andrew Carleton was able to confirm that contrails contribute to the occurrence of high-level clouds. Read more
Contrails (short for "condensation trails") or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals. Read more
Anyone who has ever seen a streaky line of vapor, known as a contrail, behind a high-flying aircraft knows that airplanes can produce their own clouds. But in rarer cases, aircraft can also punch round holes, such as the one over Antarctica pictured here, or carve long channels through existing, natural clouds. Those formations arise from the strong cooling effects of airflow over a planes propeller blades or a jetliners wing. Read more