GLOBAL WINDS AND LOCAL WINDS

• Wind is the movement of air.
• Wind is caused by:

  1. Differences in temperature
  2. Differences in pressure
• DIFFERENCES IN TEMPRERATURE:

  1. Warm air rises - makes molecules move faster and spread out ; Makes the air less dense (rise)
  2. Cold Air sinks - makes molecules move slower and group together ; makes the air more dense (sink)
• DIFFERENCES IN PRESSURE:

  1. Rising air creates LOW pressure - if air is lifted UP, there is LESS air pushing down on earth.
  2. Sinking air creates HIGH pressure - if air is SINKING, then air is pushing down on earth with a HIGH amount of pressure.
• THE CREATION OF WIND:

  1. Differences in temperature cause air to rise up & sink.
  2. Rising and sinking air creates high & low pressure.
  3. The atmosphere equals out pressure by moving air from high to low pressure.
• THE CREATION OF WIND:

  1. HEATing the air, DECREASES the pressure
  2. COOL air, replaces warm air (HIGH PRESSURE)
  3. As air goes from high - low pressure winds form.
• Wind is a horizontal movement of air.
• There are 2 types of winds : local & global.
• Global winds are patterns of wind that happen all over the world. They are created by the spin of the earth & difference in temperatures.
• Polar Easterlies are winds that blow close to the north and south poles. (They blow away and curve east to west) (They are cold, dry winds)
• Prevailing Westerlies are winds that predict most of our weather. (Blow from west to east)
• Trade winds are winds that circle near the equator. They are used by ships for sailing the ocean.
• Local winds are winds that are in one particular area.

  TYPES OF LOCAL WINDS

  1. Sea Breeze
  2. Land Breeze
  3. Mountain Breeze
  4. Valley Breeze
• Sea Breeze : Air moves from the sea during the day.
• Convection is the main way the atmosphere is heated.
• Land Breeze : Air moves from the land at night.
• Valley Breeze : The sun heats the valley air quickly and the warm air rises and moves up the mountain.
• Mountain Breeze : At night the mountain air cools faster than the valley ; cool Air sinks down the mountain and wind moves in the opposite direction.