Naturalists at Large Desert Slide Show

1. Deserts & Winds

2. “We don’t survive the desert,
we live here”
- Pima Indian

3. Deserts & winds
1) Deserts: where & why
Earth’s dry regions: 30% of all land
2 climate types of dry regions:
q desert (arid)
q steppe (semi-arid, surrounds deserts)

4. Deserts & winds
1) Deserts: where & why
What causes deserts?
Important factors:
Global distribution of
q air pressure
q wind
Relationship between
q rainfall
q evaporation
www.weatherchannel.com

5. Deserts & winds 1) Deserts: where & why

6. Deserts & winds
1) Deserts: where & why
Low-latitude deserts
(recall: “latitude” = east-west line on the globe)
x Tropic of Cancer
x Tropic of Capricorn
In contrast….
x Equator:
x hot air
x rises to 15-20 km
x low pressure belt

7. Deserts & winds 1) Deserts: where & why

8. Deserts & winds 1) Deserts: where & why

9. Deserts & winds 1) Deserts: where & why

10. Deserts & winds
1) Deserts: where & why
Middle-latitude deserts
x exist in rain shadows.

11. Deserts & winds
2) Basin and range
Basin and range
x mountainous desert landscape

12. Deserts & winds
2) Basin and range
Basin and range
x mountainous desert landscape

13. Deserts & winds 3) Wind erosion/ deposits
Wind erosion: Important in arid environments
Example: Types of sand dunes:
Sand dune shape depends on:
Flat
or hilly?
How much sand?
Winds steady or intermittent?
Wind direction constant?
Vegetation present?

15. Deserts & winds 3) Wind erosion/ deposits
Sand dune formation

16. Deserts & winds 3) Wind erosion/ deposits
Desert pavement

17. Deserts & winds 3) Wind erosion/ deposits

19. Deserts & winds 3) Wind erosion/ deposits
Graded beds