1. Deserts and Wind Action
Lecture 15
Deserts and Wind Action

2. Lecture Outline I Deserts II Wind Action A) Erosion III Conclusions
A) Characteristics
B) Distribution
C) Southwest United States
i. The Great Basin
ii. The Colorado Plateau
II Wind Action
A) Erosion
B) Transportation
C) Deposition
III Conclusions
Lecture 3 ii

3. Characteristics of Deserts
< 25 cm rain per year
sparse rugged vegetation
two climatic types
arid deserts
semiarid steppes

4. Distribution of Deserts

5. Climate Controls Solar Radiation and Heat Transfer

6. Climate Controls Atmospheric Heat Transfer
Three Cell Model
Hadley Cell
Ferrell Cell
Polar Cell

7. Climate Controls Oceanic Heat Transfer

8. Climate Controls Oceanic Heat Transfer – Thermohaline Circulation

9. Distribution of Deserts Controlling Climatic Factors
Atmospheric Circulation
Rain Shadow
Cold Ocean Currents
Continentality

10. Distribution of Deserts Atmospheric Circulation

11. Distribution of Deserts Atmospheric Circulation

12. Distribution of Deserts Atmospheric Circulation - The Sahara

13. Distribution of Deserts Rain Shadow

14. Distribution of Deserts Rain Shadow - The American Southwest

15. Distribution of Deserts
Cold Ocean Currents

16. Distribution of Deserts Cold Ocean Currents - The Namib
Sea Surface Temperature (oC) - 03/17/02
Naval Research Laboratory, Stennis Space Center

17. Distribution of Deserts Cold Ocean Currents - The Namib

18. Distribution of Deserts Continentality - The Gobi

19. Deserts of the American Southwest
The Great Basin (Basin and Range)
The Colorado Plateau

20. Deserts of the American Southwest
Water Bodies – Arroyos

21. Deserts of the American Southwest The Great Basin
rugged mountain ranges
separated by flat valleys
fault-controlled topography

22. Deserts of the American Southwest The Great Basin

23. Desert Landforms of the American Southwest The Great Basin

24. Desert Landforms of the American Southwest Great Basin Landforms - Alluvial Fan
alluvial fan - an outspread, gently sloping mass of alluvium deposited
by a stream, particularly in an arid or semi-arid region
where a stream issues from a narrow canyon onto a plain
or valley floor.

25. Desert Landforms of the American Southwest Great Basin Landforms – Bajada
bajada - a broad, gently inclined detrital surface extending from the base
of a mountain range out into an inland basin, formed by the
lateral build-up of a series of alluvial fans.

26. Desert Landforms of the American Southwest Great Basin Landforms - Playa
playa - a dry, barren area in the lowest part of an
undrained desert basin.
playa lake - a shallow, intermittent lake in an arid
region.

27. Desert Landforms of the American Southwest Great Basin Landforms - Pediment
pediment - a broad gently sloping erosion
surface or plain of low relief,
typically developed by running
water, in an arid or semiarid
region at the base of an abrupt
and receding mountain front.

28. Desert Landforms of the American Southwest Great Basin Landforms – Inselberg

29. Desert Landforms of the American Southwest Great Basin Landforms Evolution

30. Deserts of the American Southwest The Colorado Plateau
beds of flat-lying sedimentary rocks
>1500m above sea level due to uplift
marked by monoclines

31. Deserts of the American Southwest Colorado Plateau Landforms
plateau- a relatively elevated area of comparatively flat land bounded on
at least one side by cliffs
mesa - a broad flat-topped hill
butte - a narrow hill of resistant rock with a flat top and very steep sides

32. Desert Landforms of the American Southwest The Colorado Plateau – Monocline
monocline - a local steepening in an otherwise uniform gentle dip

33. Wind Action
Erosion
Transport
Deposition

34. Wind Action Erosion

35. Wind Action Erosion - Blowout

36. Wind Action Erosion - Deflation

37. Wind Action Erosion - Ventifacts

38. Wind Action Transportation

39. Wind Action Transportation - Dust Storms

40. Wind Action Deposition – Dunes

41. Wind Action Deposition – Dune Migration

42. Wind Action Deposition – Dune Morphology

43. Wind Action Deposition – Controlling Factors on Dune Morphology

44. Wind Action Deposition - Barchan Dunes

45. Wind Action Deposition – Transverse Dunes

46. Wind Action Deposition – Barchanoid Ridge Dunes

47. Wind Action Deposition – Star Dunes

48. Wind Action Deposition – Parabolic Dunes

49. Wind Action Deposition – Longitudinal Dunes