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Global Wind Patterns. What is Wind?. Wind is the movement of air from an area of higher pressure to an area of lower pressure . Warmer air expands , becoming less dense than colder air. This causes air pressure to be generally lower where air is heated. The Coriolis Effect. - PowerPoint PPT Presentation
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Global Wind Patterns
What is Wind?
• Wind is the movement of air from an area of higher pressure to an area of lower pressure. Warmer air expands, becoming less dense than colder air. This causes air pressure to be generally lower where air is heated.
The Coriolis Effect
http www.youtube.com/watch?v=mcPs_OdQOYU
• Coriolis Effect – Rotation of the Earth causes moving air and water to change directions• Northern Hemisphere winds curve to the right• Southern Hemisphere winds curve to the left.
• The Coriolis Effect - The tendency for any moving body on or above the earth's surface, such as an air or water current, to drift sideways from its course because of the earth's rotation. This affects Earth’s winds and water movement. Air moves to the right in the Northern Hemisphere. In the Southern Hemisphere, they move to the left.
Warm Moist Air Rises
Warm Moist Air Rises
Cool Dry Air Sinks
Cool Dry Air Sinks
Warm Moist Air Rises
Cool Dry Air Sinks
Cool Dry Air Sinks
Cold Moist Air Rises
Cold Moist Air Rises
Warm Moist Air Rises
Cool Dry Air Sinks
Cool Dry Air Sinks
Cold Moist Air Rises
Cold Moist Air Rises
Very Cold Air Sinks
Very Cold Air Sinks
Warm Moist Air Rises
Cool Dry Air Sinks
Cool Dry Air Sinks
Cold Moist Air Rises
Cold Moist Air Rises
Very Cold Air Sinks
Very Cold Air Sinks
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Wind Moves from HIGH to LOW
Objects are deflected to the
RIGHT in the Northern Hemisphere
Global Winds• Global Winds - Wind gets its name from the
direction it is blowing FROM!
Winds in the Upper Troposphere
• The jet stream is a current of fast moving air found in the upper levels of the troposphere.
Jet Stream• Discovered in 1940’s• Can be found in the upper troposphere• Strong high speed and high pressure• Moves west to east across the US, movingstorms
• The polar jet stream forms at the boundary of cold, dry polar air to the north and warmer, more moist tropical air to the south.
What brings certain weather phenomenon?
El Nino La Nina• occurs when the surface
temperature rises above the normal water temperature in the Equatorial Pacific Ocean creating more humidity in the atmosphere
• Known to increase number of hurricanes
• Occur more frequently (every 3-7 years)
occurs when the surface temperature falls below the normal water temperature in the Equatorial Pacific Ocean creating a more dry atmosphere
Known to create drought conditions
GLOBAL FORCES• The following global forces can affect the
formation of surface currents.
Equator
Earth’s Rotation
Continental DeflectionGlobal Forces
Continental Deflection
Since the Earth’s surface is not fully covered by water, currents cannot move freely around the world. So when surface currents meet continents, they deflect, or change direction.
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Predict what will happen with each labeled area.
Equator
Earth’s Rotation
Continental Deflection
Coriolis Effect
Global Forces
Coriolis Effect
The Earth’s rotation causes surface currents to move in curved paths rather than in a straight line.
North Pole
Earth’s Rotation
Equator
Earth’s Rotation
Continental Deflection
Coriolis Effect
Global ForcesGlobal Winds
Global WindsGlobal winds are affected by their latitude and the Coriolis Effect. In the tropics winds blow from the east to the west. In more temperate areas, the winds blow from the west to the east. Near the poles the winds blow from the east to the west.
Tradewinds
Tradewinds
Westerlies
Westerlies
Polar Easterlies
Polar Easterlies
Equator
Earth’s Rotation
Continental Deflection
Coriolis Effect
Global Forces TransparencyGlobal Winds
Deep Ocean Currents
Deep Ocean Currents
• Deep cold currents move water toward the equator.
• Cold water rises to replace warm water leaving.
• Warm water travels near the surface toward polar regions.
• Warm water replaces cold water.
Equator
Earth’s Rotation
Continental DeflectionSince the Earth’s surface is not fully covered by water, currents cannot move freely around the world. So when surface currents meet continents, they deflect, or changedirection.
Coriolis EffectThe Earth’s rotation causes surface currents to move in curved paths rather than in a straight line.
Global Forces Global WindsGlobal winds are affected by their latitude and the Coriolis Effect. In the tropics winds blow from the east to the west. In more temperate areas, the winds blow from the west to the east. Near the poles the winds blow from the east to the west.
Deep Ocean CurrentsDeep cold currents move water toward the equator.Cold water rises to replace warm water leaving.Warm water travels near the surface toward polar regions.Warm water replaces cold water.
