Assignment

Lab: Arid Environments and Aeolian Geomorphology

Introduction

Desert environments are geographic regions where potential evapotranspiration normally exceeds precipitation. The distinction of this environment is usually drawn where precipitation is less than 500 mm per year. Many have drawn distinctions between extremely arid (consistently have 12 consecutive months without rainfall), and lands (250 mm or less), and semiarid lands (250-500 mm). Regardless of the total rainfall the desert environment results in sparse vegetation, minimal animal habitation and human settlement. These harsh landscapes make up about 33% of the Earth's surface and exist in both warm and cold regions. They are not constrained by latitude, longitude or elevation. The reason for the geographical location of these deserts is driven by variables within the global, regional, and local climate systems, and this climatic regime ultimately influences the geomorphic processes that work within those environments.

1. Given your knowledge of atmospheric processes and climate controls and using Google Earth, try to identify areas you think are deserts on Earth's surface. No need to zoom in too close, just locate them from the global view, but feel free to rotate the planet and zoom in if you think you've found one. Limit them to the largest and most obvious features from the global perspective. As you locate them, please draw a rough outline in these areas with a pencil on your blank world map.

2. What did you use to identify the deserts? In a few sentences, explain the criteria you used to distinguish them from non-desert areas.

3. Did you notice any commonalities about where these deserts were located? Feel free to zoom in and investigate the deserts you located to answer this. If yes, please explain. If no, describe why they are not similar. (Hint: Are there similar latitudes? Physical landscapes? Textures? Colors? Vegetation?)

4. What kind of desert do you think the Sahara Desert is?

5. Why do you think this? In a paragraph, describe what you think the dominant processes are that are responsible for the arid environment that exists here. Do not be general about this. Try to be very specific for this desert given what you know.

6. The Sahara is the largest desert in the world. Why do you think it is so large?

7. What kind of desert do you think the Atacama Desert is?

8. Why do you think this? In a paragraph, describe what you think the dominant processes are that are responsible for the and environment that exists here. Do not be general about this. Try to be very specific for this desert given what you know.

9. The Atacama is the driest desert in the world. IThy do you think this desert is so extremely arid?

10. How would you classify the Sonoran Desert?

11. In a paragraph, describe what you think the dominant processes are that are responsible for the arid environment that exists here. Do not be general about this.

"Try to be very specific for this desert given what you know.

12. The Sonoran Desert is home to some unique species of large vegetation like the Saguaro Cactus. Why do you think this desert is able to support such vegetation?

Explain using the climograph of Tucson that follows (Figure 10.11).

13. Using Google Earth, go to White Sand Dunes, New Mexico, in the Search Box in the upper left of the screen. This is one of the most spectacular sand dune fields on Earth. When you have located the White Sand Dunes please look over the entire sand dune field. Look for locations that have barchan dunes and point the map over that area. lVrite down the latitude and longitude of a (or a group of) barchan dune.

14. Now that you have located barchan dunes, see if you can find parabolic dunes. If you are not sure of the difference, please see the diagrams in Figure 10.15 and the previous description. Once you find parabolic dunes, please write down the latitude and longitude of that location.

15. Which way is the dominant wind blowing across these sand dunes?

16. Using Google Earth, go to the Namib Desert. You will immediately notice that it is a very strange landscape. Sand dunes are everywhere! This is one of the largest sand seas in the world. What kinds of sand dunes do you notice? Please write the latitude and longitude next to the different dune type or types you observe. You may notice more than one kind, and that is OK.

7. What do you think the dominant wind directions are based on what you can see in the sand dunes?

18. Why do you think the Namib Desert exists in this location? Think of the atmospheric circulation, oceanic circulation and physical landscapes in and surrounding the area. In a few sentences, describe why this desert exists.

19. Using Google Earth, go to the Grand Erg Oriental. This is a section of the Sahara Desert in northern Africa. You are going to have to zoom in very close and go slightly north on the map until you see a bunch of small dots or hills on the landscape. These dots/hills are individual sand dunes. What kind of dunes are these?

20. What do you think the dominant wind directions are here?

https://www.dropbox.com/s/h33kik3m2ndzci3/Lab-Arid-Environments-and-Aeolian-Geomorphology.pdf?dl=0