19.3: Global Wind Patterns
http://www.toonpool.com/user/589/files/wind_farm_desert_island_128775.jpg
Factors that Affect Winds• Temperature difference between
equatorial regions and the poles• Rotation of the Earth www.physicalgeography.net
wattsupwiththat.com
Factors that Affect Winds• Locations of the Continents• Time of year• Local topography (mountains,
valleys, plains, etc.)
science-class.netwallpaperstock.net
Winds on a Non-rotating Earth• Warm air near the equator
would rise and move toward the poles aloft
• Cold air near the poles would move toward the equator at the surface
Winds on a Non-rotating Earth
http://universe-review.ca/I09-15-circulation1.jpg
Effects of Earth’s Rotation• Coriolis effect prevents air from
flowing straight to equator from poles
• Also, air from the equator cools & sinks long before reaching the poles
Three-Celled Circulation Model
3-Celled Circulation Animation
Three-Celled Model Weaknesses
1. Mid-latitude (between 30° & 60° latitude) winds are oversimplified
2. Effects of continents or seasons not accounted for
3. Upper-level winds are more complicated than the model shows
Three-Celled Model Strengths
1. Latitudes other than between 30° & 60° are fairly accurate
2. Model is an average; good for climate studies (long-term pattern)
Wind and Pressure Belts• Intertropical Convergence Zone
(ITCZ): low pressure zone created by maximum heating at the equator
principiojoanne2196.blogspot.com
Wind and Pressure Belts• The ITCZ is hot & humid with little
or no wind; rain is frequent (doldrums)
tnhsprgteam.blogspot.com
Wind and Pressure Belts• ITCZ encircles the Earth; migrates
north and south depending on the season
en.wikipedia.org
The ITCZ: Can U find it?
http://cawcr.gov.au/bmrc/clfor/cfstaff/jmb/03May15a.html
Three-Celled Circulation Model
www.newmediastudio.org