EOLIAN AND ARID LANDSCAPES

Please refer to the GETTING STARTED module to learn how to maneuver through, and how to answer the lab questions, in the Google Earth () component.

KEY TERMS

You should know and understand the following terms:

Abrasion

Loess

Rain shadow

Barchan dune

Longitudinal dune

Reversing dune

Barchanoid Ridge dune

Mesa

Star dune

Butte

Parabolic dune

Sub-tropical high

Canyon

Pinnacle

Transverse dune

Desertification

Plateau

Yardang

Dome dune

Playa

LAB LEARNING OBJECTIVES

After successfully completing this module, you should be able to do the following tasks:

· Identify erosional processes and features created by wind

· Identify depositional processes and features created by wind

· Describe the processes that create eolian landforms

· Distinguish different sand dune types

· Calculate slope

· Interpret the topographic profile of a landscape

INTRODUCTION

This module examines the eolian processes and arid environments. Topics include dune classification, eolian processes and features, and arid landforms. While these topics may appear to be disparate, you will learn how they are inherently related. The module starts with four opening topics, or vignettes, which are found in the accompanying Google Earth file. These vignettes introduce basic concepts of the eolian and arid landscapes. Some of the vignettes have animations, videos, or short articles that will provide another perspective or visual explanation for the topic at hand. After reading the vignette and associated links, answer the following questions. Please note that some links might take a while to download based on your Internet speed.

Expandthe INTRODUCTION folder and then check Topic 1: Introduction.

Read Topic 1: Introduction.

Question 1: Which of the following was not provided in the Introduction as a characteristic of an arid environment?

A. Little precipitation

B. Drought resistant vegetation

C. Sparse vegetation

D. Hot temperatures

Read Topic 2: Arid Land and Water

Question 2: What is not listed as a source of water for human use in arid environments in Topic 2?

A. Wells

B. Salt water

C. Oases

D. Rainfall

Read Topic 3: Hot and Cold Deserts.

Question 3: What characteristics of polar deserts make them suitable for study by planetary scientists?

A. Barren landscapes

B. Cold climate

C. Isolation

D. All of the above

Read Topic 4: Human Interaction.

Question 4: Which of the following is not one of the four techniques that humans have employed to stop desertification.

A. Covering sand dunes in petroleum

B. Building sand fences

C. Covering sand dunes in plastic

D. Planting vegetation

Read Topic 5: Eolian Landscapes.

Question 5: Where is the thickest known Loess deposit and what is the depth?

A. Kansas, 120m

B. Nebraska, 95m

C. China, 335m

D. Iran, 40m

Collapse and uncheck INTRODUCTION

GLOBAL PERSPECTIVE

Expand GLOBAL PERSPECTIVE. Double-click and select Major World Deserts.

This map shows the location of major deserts (in tan) throughout the world. It is important to note that while deserts are always considered arid environments, arid environments are not always deserts. Arid environments also include Mediterranean regions and semi-arid lands, among others. Areas where water is severely limited, eolian processes become the dominant mechanism for erosion, transportation and deposition of sediments.

Expand and select Major Cities.

This map shows the location of major cities located in arid environments. At present, such cities are placing increasing pressure on water resources and contributing to desertification.

For Questions 6 to 9, type the information provided in the Search tab in Google Earth and press Enter. When you arrive at your destination, find the information to fill in the blanks below.

Question 6: Cairo, Egypt (population : X)

Latitude/Longitude:

A. 30N, 31E

B. 31N, 30E

C. C. 30S, 31W

D. D. 31N, 30 W

Question 7: Riyad, Saudi Arabia (population : X)

Latitude/Longitude:

A. 24N, 46E

B. 46S, 24E

C. 24N, 46W

D. 46N, 24W

Question 8: 12° 2’49.53″S, 77° 0’37.67″W (population : X)

City:

A. Santiago

B. Lima

C. Bogotá

D. Paracas

Question 9:33°22’22.03″N, 112°34’48.60″W (population : X)

City:

A. Las Vegas

B. Los Angeles

C. Phoenix

D. Tucson

Collapse and uncheck GLOBAL PERSPECTIVE

LOCATION OF ARID REGIONS

The following factors influence the location of deserts:

· Subtropical high pressure systems

· Rain shadow effect

· Ocean current temperatures

· Distance to large bodies of water

It is important to note that two or more of these factors may influence the location of deserts.

Expand the LOCATION OF ARID REGIONS folder. Double‑click and select Sahara Desert.

Subtropical high pressure systems are generally located between 15 and 30 degrees north and south. At these locations, high pressure systems exist, with descending air warming as it falls. The result is a climate of hot temperatures and little precipitation. The Sahara desert is a good example of a desert formed because of a subtropical high pressure system.

Double‑click and select Oregon Great Sandy Desert.

The rain shadow effect can be seen on the leeward side on mountain ranges. An air mass approaching a mountain range is forced upward by the mountains and precipitation results on the windward side of the range. On the leeward side, the air mass loses most of its moisture and warms as it descends the mountain range. The result is a semi-arid to arid landscape. The Oregon Great Sandy desert is a good example.

Double‑click and select Atacama Desert.

Cold ocean currents do not significantly heat air mass above them. The result is an air mass containing little moisture, and when the air mass reaches land, precipitation is almost non-existent. The Atacama Desert is a good example.

Double‑click and select Gobi Desert.

The distance to a large body of water such as an ocean or sea, is a factor, because water bodies can provide moisture to air masses, which in turn lead to precipitation. The further an area is from a large body of water, the less likely it is to receive moisture. The Gobi Desert straddling the China-Mongolia border is an example of an arid region far from a large body of water.

Double‑click and select Namib Desert.

Question 10: Which of the following factors is mainly responsible for the location of the Namib Desert?

A. Subtropical high pressure

B. Rain shadow effect

C. Cold ocean currents

D. Distance from large body of water

Question 11: Why did you pick the answer, or answers, you did in question 10?

A. Lack of clouds in imagery shows it is a subtropical high area

B. The coastal beaches create a rain shadow inland

C. The cold ocean current limits moisture in atmosphere creating the coastal desert

D. The desert is a long distance from any inland body of water

Double‑click and select Patagonia.

Question 12: Which of the following factors are mainly responsible for the location of the arid lands in Patagonia?

A. Subtropical high pressure

B. Rain shadow effect

C. Cold ocean currents

D. Distance from large body of water

Question 13: Why did you pick the answer, or answers, you did in question 12?

A. It is a noted subtropical high area

B. The coastal mountains create a rain shadow inland

C. The cold ocean current limits moisture in atmosphere creating the coastal desert

D. The desert is a long distance from any inland body of water

Double‑click and select Taklimakan Desert.

Question 14: Which of the following factors are mainly responsible for the location of the Taklimakan Desert?

A. Subtropical high pressure

B. Rain shadow effect

C. Cold ocean currents

D. Distance from large body of water

Question 15: Why did you pick the answer, or answers, you did in question 14?

A. It is a noted subtropical high area

B. The coastal beaches create a rain shadow inland

C. The cold ocean current limits moisture in atmosphere creating the coastal desert

D. The desert is a long distance from any inland body of water

Double‑click, and select, Mojave Desert.

Question 16: Which of the following factors are mainly responsible for the location of the Mojave Desert?

A. Subtropical high pressure

B. Rain shadow effect

C. Cold ocean currents

D. Distance from large body of water

Question 17: Why did you pick the answer, or answers, you did in question 16?

A. It is a noted subtropical high area

B. The arid environment creates a rain shadow inland

C. The cold ocean current limits moisture in atmosphere creating the coastal desert

D. The desert is a long distance from any body of water

Collapse and uncheck LOCATION OF ARID REGIONS