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
 
  development
 
  cloud types
 
> precipitation

Precip Processes
 
  states of water
 
> upward motion
 
  rain or snow

User Interface
 
  graphics
> text

NOTE: We've guessed that you're not using a client that supports colored tables and have tried to compensate. Low graphics mode looks much better on clients that do... we recommend switching to Netscape 3.0 or Microsoft Internet Explorer.
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Upward Motion
key process in producing clouds and precipitation

Imagine a block of air, or air parcel, rising upwards through the atmosphere. The walls of this block are solid so that the air inside does not mix with the outside air.


Since temperature of the atmosphere decreases with height, the temperature of the air parcel cools as it rises upwards.


If the air cools to its saturation point, the water vapor "condenses" (changes from gas to liquid) to form tiny water droplets. Since it requires an extremely large number of water droplets to produce a cloud, the air must contain enough moisture otherwise a cloud is unlikely to form, let alone precipitation which requires even more.


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.