Chapter 1 The Desert Environment

Chapter Outline

Introduction
   Deserts defined
Causes and Effects of Aridity
   Continental location
   Cold coastal currents
   Rain shadows
   Horse latitudes
   Measuring aridity
   Climate diagrams
   Heat
Deserts Defined II
The Desert Landscape
   Landforms: the work of water
   Soils and dunes
The North American Desert
   Intermountain Desert
   Mojave Desert
   Sonoran Desert
   Chihuahuan Desert

Web Resources

Overview of the Desert  Defines and describes the causes of the deserts. From Desert Digital Library.

Geomorphology of the Desert  From DesertUSA.

Desert Varnish and Lichen Crust Microscopic Organisms Color Desert Rocks  From DesertUSA.

Sand Dunes: A Phenomenon of Wind  A wonderful introduction to dunes and the life that resides there. From Wayne's Word.

North American Deserts  Another summary of the North American Deserts with links to more details about the individual deserts and the common plants and animals. From DesertUSA.

Colorado Plateau Semi-Desert, Chihuahuan Semi-Desert, American Semi-Desert and Desert (the subtropical deserts), Intermountain Desert and Semi-Desert, the northern Intermountain Semi-Desert pages describe the deserts as delineated by the USDA Forest Service ecoregions classification. These are rather technical descriptions but a very well supported classification of ecoregions.

The Chihuahuan Desert  This page includes links to other Chihuahuan Desert resources. From Desert Digital Library.

Sonoran Desert Naturalist has some interesting links to pages concerning the Sonoran Desert.

Study Questions

1. The Sonoran Desert of Baja California, the Atacoma Desert of South America, and the Namib Desert of Africa all reach to the sea yet they are some of the most arid regions on Earth. Explain.

2. Much of the North American Desert lies in a rain shadow. Describe how it is that the leeward side of mountains are drier and warmer than the windward side.

3. Most of the Earth's deserts lie near 30° north and south of the equator. Explain how it is that this region is relatively dry.

4. Total precipitation measures the amount of water that falls, but there are other factors that determine the aridity of a region. Explain.

5. Climate diagrams are graphical depictions of climate. Given a climate diagram, describe the seasonal patterns of temperature and moist and dry seasons for the station.

6. Why are diurnal fluctuations in temperature more drastic in the desert than in more humid environments?

7. Despite the aridity, desert landscapes are largely defined by water. Describe how a desert, with infrequent precipitation, can be so influenced by water. Include a description of how major desert landforms originate.

8. Describe desert soils. Compare and contrast desert pavement and cryptogamic crust.

9. For each of the four North American deserts: a) Clearly place the desert on a North American map. b) List the major causes of aridity for the particular desert. c) Describe the general climatic characteristics of the desert. d) Based on vegetation characteristics, distinguish the desert from the other three deserts.

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