What are contrails??

Question

Do you think that its the goverment spraying us? Do you think its alien spacecraft? Do you think its the atmospheric conditions at the time of the plane passing? We live near Cleveland Ohio and last week there was a full grid pattern in the sky and a big hubbbub on the radio about it.

Answer 1

The word 'contrail' is made up from the two words 'condensation trail' A normal contrail happens when the hot exhaust from the jet engines come in contact with the cold air and it creates a vapor by turning any moisture in the air into a vapor. They are also known as vapor trails.

Answer 2

The condensation trail emitted by jet aircraft exhaust are called contrails. Contrails form when hot humid air from jet exhaust mixes with environmental air of low vapor pressure and low temperature. The mixing is a result of turbulence generated by the engine exhaust. Cloud formation by a mixing process is similar to the cloud you see when you exhale and "see your breath". The figure below represents how saturation vapor pressure varies as a function of temperature. The blue line is the saturation vapor pressure for ice as a function of temperature (in degrees Kelvin). Air parcels in the region labeled saturated will form a cloud. Imagine two parcels of air, A and B, as located on the diagram. Both parcels are unsaturated. If B represents the engine exhaust, then as it mixes with the environment (parcel A) its temperature and corresponding vapor pressure will follow the dotted line. Where this dotted line intersects the blue line is where the parcel becomes saturated, and a cloud will form.

If you are attentive to contrail formation and duration, you will notice that they can rapidly dissipate or spread horizontally into an extensive thin cirrus layer. How long a contrail remains intact depends on the humidity structure and winds of the upper troposphere. If the atmosphere is near saturation the contrail may exist for some time. On the other hand, if the atmosphere is dry then as the contrail mixes with the environment it dissipates. Contrails are a concern in climate studies as increased jet aircraft traffic may result in an increase in cloud cover. It has been estimated that in certain heavy air-traffic corridors, cloud cover has increased by as much as 20%. An increase in cloud amount changes the region's radiation balance. For example, solar energy reaching the surface may be reduced, resulting in surface cooling. Contrail clouds also reduce the terrestrial energy losses of the planet, resulting in a warming. Jet exhaust also plays a role in modifying the chemistry of the upper troposphere and lower stratosphere. NASA and the DOE are sponsoring a research program to study the impact contrails have on atmospheric chemistry, weather and climate.

In the series of satellite images below you can investigate the duration of contrails. The satellite images are from the GOES-8 visible channel. Each image is separated in time by approximately 15 minutes. The GOES-8 image has a spatial resolution of approximately 1 km. The satellite image is a view of upper midwest including southern Wisconsin and northern Illinois. Contrails were observed from the ground during this period. At this wavelength, the GOES-8 imager is measuring the amount of radiant energy reflected by the surface and the clouds. The whiter a given portion of the image, the larger the amount of reflected visible light. White portions of the image represent thick clouds and dark regions are water or heavily vegetated regions. Contrails show up on the image as white streaks, similar to how they appear from a surface view.

Answer 3

One of the byproducts of combustion of hydrocarbon fuels (or hydrogen, for that matter) is water vapor. As the water vapor is exhausted with the rest of the..well...exhaust it condenses into water droplets and freezes, forming a condensation trail or contrail. It isn't only turbines that create contrails..they are created by all types of hydrocarbon-burning engines (hence, the contrails from large piston-engined bombers in world war II.

Answer 4

Contrails is the short form of condensation trails. It is the exhaust from aircraft engines when they fly at an altitude above the freezing point. Just like a car's exhaust becomes visible on a freezing cold day.

Answer 5

Contrails are condensation trails (sometimes vapour trails): artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices which precipitate a stream of tiny ice crystals in moist, frigid upper air. Contrary to appearances, they are not air pollution as such, though might be considered visual pollution.

Answer 6

The trails of condensate that forms behind jet engines at high altitudes. It is not aliens. It is not the government spraying us, they would use something invisible.