Global Winds and Climate Winds Caused by a

Global Winds and Climate

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?

Temperature and Pressure • As pressure increases, temperature increases • As pressure decreases, temperature decreases. – There is less pressure on the top of a mountain. What’s the temperature at the top? Cold or Warm? • Cold air has a higher pressure. Warm air has a lower pressure.

Let’s 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?

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.

Land Breezes and Sea Breezes Sea 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.

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.

Global Winds and Pressure Systems

Climate Zones

High Pressure = dry, sunny Low Pressure = Cloudy, wet

Local Climate • Affected by geography – Continentality – Rain Shadows – Elevation

Continentality • Coastal areas are more temperate than inland areas. – Due to water’s slow heating and cooling compared to land.

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.

Elevation • The higher you go, the colder it gets.