WW2010
University of Illinois

WW2010
 
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Online Guides
 
  introduction
 
> meteorology
 
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Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
> hydrologic cycle
 
  light, optics
 
  midlatitude cyclones
 
  severe storms
 
  weather forecasting

Hydrologic Cycle
 
  introduction
 
  water budget
 
  evaporation
 
> condensation
 
  transport
 
  precipitation
 
  groundwater
 
  transpiration
 
  runoff
 
  summary

condensation
 
  introduction
 
> convection
 
  cyclones
 
  fronts
 
  topography

User Interface
 
  graphics
> text

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Convection
atmospheric motions in the vertical direction

In meteorology, convection refers primarily to atmospheric motions in the vertical direction. As the earth is heated by the sun, different surfaces absorb different amounts of energy and convection may occur where the surface heats up very rapidly. As the surface warms, it heats the overlying air, which gradually becomes less dense than the surrounding air and begins to rise.

The bubble of relatively warm air that rises upward from the surface is called a "thermal".

A simple demonstration of condensation through convection can be performed by placing a pot of water on a heated stove. The burner represents the heating of the earth's surface by the sun, while the water and the air above it represent the atmosphere. As the bottom of the pot (earth's surface) begins to heat the water (lower atmosphere), warmer and less dense water evaporates and rises (thermal) into the drier, colder air above the pot (middle atmosphere). This causes the thermals to cool and water vapor within to condense, forming a small cloud, or steam, that is visible above the pot of heated water.

[Image: convective cloud (83K)]
Photo by: Bramer

This same process occurs in the real atmosphere as the water vapor within rising thermals condenses to form a cloud, as occurred in the example shown above.



introduction
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.

cyclones