WW2010
University of Illinois

WW2010
 
  welcome
 
> online guides
 
  archives
 
  educational cd-rom
 
  current weather
 
  about ww2010
 
  index

Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
  reading maps
 
  projects, activities

Meteorology
 
  introduction
 
  air masses, fronts
 
> clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
  light, optics
 
  midlatitude cyclones
 
  severe storms
 
  weather forecasting

Clouds, Precipitation
 
  introduction
 
  mechanisms
 
  precip processes
 
  high level clouds
 
  mid level clouds
 
  low level clouds
 
  vertically developed
 
> other cloud types

Other Cloud Types
 
> contrails
 
  billow clouds
 
  mammatus
 
  orographic
 
  pileus

User Interface
 
  graphics
> text

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Contrails
condensation trails

A contrail, also known as a condensation trail, is a cirrus-like trail of condensed vapor (often resembling the tail of a kite) that is produced by jet aircraft flying at high altitudes. Contrails are produced at altitudes high enough for water droplets to freeze in a matter of seconds before they evaporate. Temperatures at such altitudes are typically below -38 degrees Celsius.

[Image: photo of contrail in tact (78K)]


Contrails form through the injection of water vapor into the atmosphere by exhaust fumes from a jet engine. If there is sufficient mixing between the cold upper tropospheric air and the hot exhaust gases to produce a state of saturation, ice crystals will develop. Even tiny nuclei released in the exhaust fumes may be sufficient enough to generate ice crystals.

[Image: contrail spead apart by upper level winds (70K)] Contrails spread apart and evaporate with time. If the air in which the cloud develops has a low relative humidity, the cloud particles will quickly evaporate. However, even in the presence of higher relative humidities, upper level winds can spread contrails apart, forming a horizontal sheet-like cloud. For a contrail to remain in tact for a long period of time, the air must have high a relative humidity and light winds.


Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.