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Continental & Local Winds

Objectives:

    1.    Describe the effects of seasons and continents on wind patterns.

    2.    Explain the circulation of sea, land, mountain, and valley breezes.

Key Terms:

    monsoon

Notes: (19-4)

Because the Earth's tilt and its yearly journey around the sun, the amount of insolation the surface of the Earth receives changes as well.  With the change in insolation comes a change in surface temperatures. 

Changes in the surface temperatures cause changes in the local wind patterns.
Changes in temperature cause a change in pressure
These seasonal changes in pressure systems and wind direction cause monsoons (seasonal change in wind)

Local Winds

Local winds are described as winds that extend 100km or less that are created by local differences in temperatures.

Sea breeze
As the land heats up during the day, the density of the air over the land decreases and a local convection is established between the coastal waters and the land
Usually from late morning until late afternoon
Called on-shore wind

sea breeze circulation

  1. Warm air over land rises
  2. Sea Breeze moves inland
  3. Cumuli develop aloft and move seaward
  4. Upper level return land breeze
  5. Cool air aloft sinks over water
  6. Sea Breeze (meso-cold) Front

(www.islandnet.com/~see/weather/ graphics/photos/seabrz.gif)

Land breeze
As the land cools down during the evening and night, the density of the air over the land increases and a local convection is established between the land and the coastal waters
Usually from late afternoon until early morning
Called off-shore wind
land breeze circulation
  1. Cool air over land sinks
  2. Land Breeze moves out over water
  3. Relatively warmer water heats air which then rises
  4. Upper level return sea breeze
  5. Cool air over land sinks

(www.islandnet.com/~see/weather/ graphics/photos/landbrz.gif)

 

 

 

Last modified: March 31, 2003