1. Wind
What are winds?

2. Global Wind Patterns
Circulation of air caused by pressure and temperature
Polar regions are high pressure zones
Equator is a low pressure zone
Warm air is less dense, and rises
Cold air is more dense, and sinks

3. Circulation Affected by Earth’s Rotation
Northern Hemisphere deflects to the right
Southern Hemisphere deflects to the left
This is caused by the Coriolis Effect

4. Movement Low pressure, warm air rises at the equator
30 degrees N and S latitude = high pressure zone, air cools and sinks
Three looping patterns are convection cells
Convection the heating and cooling of gas particles

6. Trade winds Between the Equator and 30 ° N and S latitude
Northeast trade winds
Southeast trade winds

7. Trade winds Doldrums: Warm air moves upward
Surface winds weak and undependable
How does this affect sailing?
Subtropical High Pressure Belt = Horse Latitudes
Why is this called the HORSE LATITUDES?

8. Westerlies Northern Hemisphere = South westerlies
Southern Hemisphere = North westerlies
30° to 60°
Creating the Subtropic Jet Stream
Constant flow of wind

9. Polar Easterlies Strongest off of Antarctica Very stormy region
Sub polar Jet Stream = Inconsistent movement of air km altitude, 100 km wide, 2-3 high
Moves at up to 500 km/hr
Determine the flight path of planes

10. Wind and Pressure Shifts
Pressure belts and Wind belts shift throughout the year
Why : location of the sun’s rays

11. Local Winds
Breezes: the movement of air that extends over a distance less than 100 km

12. Breezes
Land and water receive the same amount of energy (heat) from the sun
Land heats up and cools down faster than water
Differences in temperature create local winds

13. Sea Breeze Cool wind moving from water to land
Cool air is more dense than warm air
Cool air over water replaces warm air over land
When would this occur?
Afternoon

14. Land Breeze Cool wind moving from land to water
Cool air is more dense than warm air
Cool air over land replaces warm air over water
When would this occur?
At night

15. Valley Breeze Breeze blowing up the slope of a mountain
Warm air in valley rises up the mountain (cooler air)
When would this occur?
Daylight

16. Mountain Breeze
Breeze blowing down the slope of a mountain into the valley
Cool air in the mountains overtake warm air in the valley
When would this occur?
At dusk or sunset