Global Winds and Climate

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Global Winds and Climate
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Winds

• Caused by a difference in air pressure due to
  unequal heating of the atmosphere.
• Winds always move from High Pressure to Low
  Pressure
• -What direction
• Is the wind
• Coming from at
• point Y?

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Temperature and Pressure

• As pressure increases, temperature increases
• As pressure decreases, temperature decreases.
• There is less pressure on the top of a mountain.
  Whats the temperature at the top? Cold or Warm?
• Cold air has a higher pressure. Warm air has a
  lower pressure.

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Lets Review

• It is 60 degrees in city Z and 80 degrees in city
  Y. What direction is the wind blowing?
• What is the pressure
• at city Z compared to
• city Y?

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2 Types of Winds

• Local Winds (Sea Breezes and Land Breezes)
• Global Winds (Polar Easterlies, Tradewinds,
  Prevailing Westerlies)
• Global Winds are affected by the Coriollis
  Effect Rotation of the earth causes winds in
  the Northern Hemisphere to curve right and the
  Southern Hemisphere to curve left.

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Land Breezes and Sea BreezesSea Breeze Occur
during the Day

• During the day, the land warms up faster than the
  water.
• The warm air over the land rises,
• while the cooler air over the water sinks down
  and moves in to replace the warm air.

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Land Breeze Occur at night.

• At night, dry land cools faster than water.
• Since the land cools faster than the water, the
  air above the water is now
• warmer and less dense than the air above the
  dry land.
• Warmer air above the water is rising, drawing in
  the cooler air from the land.

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Global Winds and Pressure Systems
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Climate Zones
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High Pressure dry, sunnyLow Pressure Cloudy,
wet
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Local Climate

• Affected by geography
• Continentality
• Rain Shadows
• Elevation

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Continentality

• Coastal areas are more temperate than inland
  areas.
• Due to waters slow heating and cooling compared
  to land.

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Rain Shadows

• Air on windward side rises, cools and condenses
  because of mountains.
• Rain falls on windward side.
• Dry air is left on leeward side causing a rain
  shadow and usually a desert
• Examples Andes in Peru/Sierra Nevada in
  California.

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Elevation

• The higher you go, the colder it gets.