UN Human Development Index

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UN Human Development Index
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Wind as an Agent of Erosion, Transport, and
Deposition

• Think back to lab. What should we expect of
  eolian systems in terms of ETD?
• What environmental factors need to be present for
  eolian processes to operate?
• Where do you expect such processes?

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World Drylands
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How Wind Moves Sand
Figure 15-5
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What should happen here?
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Desert Pavement
Figure 15-2
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Desert Pavement
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Ripples Sand Transport and Deposition as a
Feedback System

• Deposition increases Height
• Height concentrates wind, more energy to do work
  (increased friction)
• Friction increases erosion transport on
  windward side
• Transport across crest gt energy drops
• Deposition on lee side

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Dunes
Fig 15-8
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Dunes and Wind

• Dunes concentrate wind on windward side
• Increases energy available to entrain and
  transport sand
• On lee side, wind energy disperses, drops sand
  grains
• Slope Angle of Repose

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Sand Supply, Wind Characteristics Combine to
Create Different Types of Dunes
Fig 15-9
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Namibia Dune System
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Loess

• Silt Deposits
• Silt is carried in suspension by relatively high
  winds, but easily deposited when wind speeds drop
• Well-drained, fertile soils with excellent
  moisture retention
• Corn Belt
• Central Europe
• Bucknell!
• Cohesion of silt particles can create steep bluffs