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

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

Land Breezes
 
low-level cooling
 
onshore flow aloft
 
circulation

User Interface
 
graphics
text

.
Land Breeze Develops
cooler air flows offshore

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

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

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

On the other hand, over land, air is accumulated at higher levels 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 land-breeze circulation.



onshore 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.

Hurricanes