NASA MODIS Image of the Day: September 19, 2011 – Contrails and smoke over central Canada
On September 8, 2011 the skies over Canada and the United States were covered with smoke and contrails.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true color image at 19:20 UTC (3:20 p.
m. Eastern Daylight Time) as it passed overhead. A thick plume of light gray smoke rose from a large wildfire in Lac La Biche County in Alberta, Canada. To the south of that fire, a smaller plume blows to the southeast from a wildfire burning in the state of Minnesota. In addition, linear clouds created from airplane exhaust, known as contrails, cross the skies, especially over Canada but also extending south into the United States. Contrails, short for “condensation trails” and also called vapor trails are artificial clouds that are created by the exhaust of aircraft engines. The hot gases exhausted from the aircraft cool rapidly in the surrounding air, and as this occurs, the cooling may precipitate microscopic water droplets, which become visible an appear much like a cloud. If the surrounding air is cold enough, tiny ice crystals may form in the contrail instead of water droplets.
