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Posts tagged Contrails

Contrails Over Jutland Peninsula, Denmark and Germany

57.0N 8.8E

June 5th, 2013 Category: Climate Change, Clouds MODISTerra

Denmark – June 4th, 2013

Condensation trails create criss-crossed lines over the Jutland Peninsula (center), the northern part of which belongs to Denmark and the southern part of which belongs to Germany. Depending on the temperature and humidity at the altitude the contrail forms, they may be visible for only a few seconds or minutes, or may persist for hours and spread to be several miles wide. Persistent spreading contrails are thought to have a significant effect on global climate.

Contrails, by affecting the Earth’s radiation balance, act as a radiative forcing. Studies have found that contrails trap outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) at a greater rate than they reflect incoming solar radiation (negative radiative forcing).

Global radiative forcing has been calculated from the reanalysis data, climatological models and radiative transfer codes. It is estimated to amount to 0.012 W/m2 for 2005, with an uncertainty range of 0.005 to 0.0026 W/m2, and with a low level of scientific understanding. Therefore, the overall net effect of contrails is positive, i.e. a warming effect.

However, the effect varies daily and annually, and overall the magnitude of the forcing is not well known: globally (for 1992 air traffic conditions), values range from 3.5 mW/m2 to 17 mW/m2. Other studies have determined that night flights are mostly responsible for the warming effect: while accounting for only 25% of daily air traffic, they contribute 60 to 80% of contrail radiative forcing. Similarly, winter flights account for only 22% of annual air traffic, but contribute half of the annual mean radiative forcing.

Contrails Over the Bay of Biscay, Spain and France – April 17th, 2013

45.1N 3.4W

April 17th, 2013 Category: Clouds, Image of the day

Spain and France – April 17th, 2013

Contrails hang in the air over the Bay of Biscay, between Spain (below) and France (right), creating criss-crossed patterns. Contrails, or condensation trails, usually occur when clouds form around the water vapor left in the air from the exhaust of passing airplanes, although they can also be triggered by the changes in air pressure in wingtip vortices or in the air over the entire wing surface.

Smoke Over Lake Manitoba, Canada

50.6N 98.3W

September 13th, 2012 Category: Clouds, Fires, Lakes

Canada and USA – August 29th, 2012

Smoke from wildfires in Canada creates a thick cloud in the upper left corner of this image, covering Lake Manitoba. The smoke blows in a southeasterly direction, towards Lake Superior (right center) and Lake Michigan (right edge, below the former). A few contrails from passing airplanes can be observed cutting through the cloud of smoke.

Smoky Haze and Contrails Over France

43.5N 4.8E

August 23rd, 2012 Category: Clouds, Fires

France – August 21st, 2012

Smoke from fires in Europe creates a grey veil over parts of France in this image. Also of note are a series of criss-crossed contrails over southern France and the Gulf of Lion. Contrails, also known as condensation trails or vapor trails, are long, thin, artificial clouds that sometimes form behind aircraft.

Contrails Over Northeastern USA

40.7N 74W

April 18th, 2012 Category: Clouds

USA - April 14th, 2012

Some clouds, criss-crossed by airplane contrails, hang over Delaware, Maryland, New Jersey and parts of Pennsylvania, in eastern USA. Although New York City is partially obscured by clouds, most of the rest of Long Island is visible, and sediments can be seen between the island and mainland New York. Sediments are also present further northeast, between mainland Massachusetts and the islands of Nantucket and Martha’s Vineyard.

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