1. WIND AND DESERTS
• Deserts
1. characterized by a lack of precipitation and high evaporation rates
i. rainfall is unpredictable
ii. when rain does fall, it is intense and of short duration
iii. type of weathering (physical or chemical)
iv. importance of running water and wind

2. Winds are driven by differential heating of the Earths Surface

4. • Deserts
2. location is determined by patterns of atmospheric circulation
i. Coriolis Force
ii. trade winds
iii. horse latitudes
iv. westerlies
v. easterlies

9. • Deserts
3. types of deserts
i. Subtropical (10°- 30°N & S latitude)
(1) Sahara
ii. Continental Interior
(1) Gobi Desert
iii. Rainshadow deserts
(1) Mohabbi desert

11. • How Does Wind Carries it Load?
1. bedload
i. saltation
2. Suspended load

12. • Wind Erosion
1. Deflation - removal of loose material by wind
i. deflation basin-blowout
ii. lag deposits
2. Abrasion - near surface effect caused by impact of saltating sand grains
i. ventifact (sand blasting)

13. • Deposition of Material by Wind
1. sand dunes

14. • Deposition of Material by Wind
1. sand dunes
i. types
(1) barchan
(a) crescent shaped
(b) tips point downwind
(c) in areas that are flat and dry
(d) little vegetation
(e) limited supply of sand
(f) constant wind direction

16. 1. sand dunes
i. types
(2) parabolic
(a) crescent shaped
(b) tips point upwind
(c) commonly in coastal areas with strong onshore winds
(d) abundant sand
(e) partial cover of vegetation

18. 1. sand dunes
i. types
(3) longitudinal (seif dunes)
(a) long, parallel ridges
(b) aligned parallel to the wind direction
(c) winds generally converge from slightly different directions
(d) m high; 100 km long

20. 1. sand dunes
i. types
(4) transverse
(a) long ridges
(b) perpendicular to the wind direction
(c) sand seas
(d) 200 m high; 3 km wide

22. • Deposition of Material by Wind
2. Loess - wind deposited silt and clay