WW2010
University of Illinois

WW2010
 
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> online guides
 
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  current weather
 
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  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

Forces, Winds
 
  introduction
 
  pressure
 
  pressure gradient
 
  coriolis force
 
  geostrophic wind
 
  gradient wind
 
  friction
 
  boundary layer wind
 
> sea breezes
 
  land breezes

Sea Breezes
 
  surface heating
 
  offshore flow aloft
 
> circulations

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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Sea Breeze Develops
cooler air flows onshore

Since the pressure at any location is determined by the weight of the air above it, the removal of air from higher levels causes the pressure at levels below to decrease. In the case of a developing sea-breeze circulation, an area of low pressure develops over land at the surface in response to the removal of air at higher levels by offshore flow. Conversely, an area of surface high pressure develops over water in response to the accumulation of air at higher levels.

These areas of high and low pressure establish a surface pressure gradient which generates an onshore flow of air at the surface, or sea breeze.

Vertical motions are induced in response to the horizontally moving air. Over land, for example, onshore flow causes air to pile up at lower levels while offshore flow removes air from higher levels. As a result, air rises from lower levels to replace the air that is being removed aloft.

On the other hand, over water, air is accumulating aloft while being removed from lower levels. In response, air descends from higher levels to replace the air that is being removed from lower levels. These rising and sinking motions complete the loop that makes up the sea-breeze circulation.

Sea breeze circulations typically penetrate inland a horizontal distance of less than 40 kilometers from shore. This is due to increased surface friction resulting from the topography of the land. As the distance from shore increases, the sea-breeze circulation weakens and is eventually dampened out by friction.



offshore flow aloft
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.

Land Breezes