GEOG 1113L Lab 8: GEOG 1113L Lab 8 Eolian Processes &
Arid Landscapes
Lab 8: Eolian Processes & Arid Landscapes
GEOG 1113L – Introduction to Landforms Lab
I. Wind Transport and Dunes
1. Describe the difference between suspension, saltation, and surface creep.
Suspension is what happens when the sand particles get suspended in midair. These particles are
small and light enough to be carried high into the atmosphere, where they can be transported
long distances.
Saltation happens when larger particles are transported in short distance jump along a part.
These particles are too heavy to be suspended, but they can be dislodged from the surface by
wind and bounce along the ground.
Surface creep happens when exposed sand is pushed or rolled along the ground. These particles
are too heavy to be suspended or saltated, so they can only be moved by rolling or sliding along
the surface.
2. Which type of wind transport contributes the most to the formation of dunes? Saltation
3. What shape does a barchan dune have? crescent-shaped sand dune
4. When a barchan dune comes across winds moving in two directions, incredibly long dunes can
form, which are called what? Linear dune
5. When the wind is perpendicular to the crest of the dune, the dune is called what? Transverse
dune
6. As seasons change and wind blows in different directions, what type of dune will form? Star
dune
7. Which dune has a U shape and forms from unidirectional wind and the presence of vegetation?
Parabolic dune
, 8. Name three types of obstacles that can drive the formation of dunes. Vegetations, Cliffs, hills,
and manmade obstacles.
9. Match the term with its proper definition.
__C__ Complex Dune A. The most basic form of a dune.
__A__ Simple Dune B. The same type of dune superimposed onto one another. __B__
Compound Dune C. Different types of dunes overlapping one another.
10. Name three important factors that drive dune formation. Time, wind regime, and sand supply.
II. Dune Profile
Read the definitions/hints within the diagram below and use them to determine which of the
Windward (Stoss) Slope
Slipface
Previous Slip Faces
Leeward Successive slip faces created as dune migrates
Direction of Dune Movement
terms provided below should be placed in each blank box.
, III. Case study: The Disappearing Aral Sea
The Aral Sea was once the fourth largest lake in the world. Over the last several decades, the lake
decreased in size by more than 80% and the Southern (larger) Aral Sea disappeared altogether. This
disappearance had devastating effects on communities in the region.
Go to NASA’s Earth Observatory site and read the article for “Shrinking Aral Sea” at
https://www.earthobservatory.nasa.gov/world-of-change/AralSea. As you watch the timelapse clip, you
will see dramatic changes in the aerial extent of the Aral Sea.
1. When did the Aral Sea begin to shrink? What caused the Aral Sea to shrink? The Aral Sea began
to shrink in the 1960s. It was caused by the diversion of water from the Amu Darya and Syr
Darya rivers for agricultural irrigation.
2. How has the shrinking lake affected the quality of the water and farmland in the region? The
shrinking of the Aral Sea has had a devastating impact on the people and environment of the
region. The poor water quality and salinized farmland have made it difficult for people to live and
farm. As the Aral Sea has dried up, fisheries and the communities that depended on them
collapsed. The increasingly salty water became polluted with fertilizer and pesticides. The
blowing dust from the exposed lakebed, contaminated with agricultural chemicals, became a
public health hazard.
3. How has the lake’s loss affected local summer and winter temperatures? The loss of the
moderating influence of such a large body of water made winters colder and summers hotter
and drier.
Step forward in time to see changes in the Aral Sea. The green region is the lake and the white
region around the lake is the result of salt deposits. The yellow boundary around the sea is the
approximate shoreline of the Aral Sea in 1960. Utilize the scale bar in the lower right corner of the
images to approximate distances.
4. What was the distance between the eastern edge of the Aral Sea in 1960 and the western edge
of the Southern Aral Sea in 2000? Compared to 2005? Compared to the distance in 2010? And,
in 2015? The distance between the eastern edge of the Aral Sea in 1960 and the western edge of
the Southern Aral Sea decreased significantly over time, from 200 km in 2000 to 0 km by 2010.
The Southern Aral Sea remained dry in 2015. This is because the Aral Sea has been shrinking
rapidly since the 1960s due to the diversion of water from its two main tributaries, the Amu
Darya and Syr Darya rivers, for irrigation purposes.
5. What was the distance change between 2000 and 2005? Between 2005 and 2010? And,
between 2010 and 2015? Does the rate of loss appear to be accelerating? The distance change
Arid Landscapes
Lab 8: Eolian Processes & Arid Landscapes
GEOG 1113L – Introduction to Landforms Lab
I. Wind Transport and Dunes
1. Describe the difference between suspension, saltation, and surface creep.
Suspension is what happens when the sand particles get suspended in midair. These particles are
small and light enough to be carried high into the atmosphere, where they can be transported
long distances.
Saltation happens when larger particles are transported in short distance jump along a part.
These particles are too heavy to be suspended, but they can be dislodged from the surface by
wind and bounce along the ground.
Surface creep happens when exposed sand is pushed or rolled along the ground. These particles
are too heavy to be suspended or saltated, so they can only be moved by rolling or sliding along
the surface.
2. Which type of wind transport contributes the most to the formation of dunes? Saltation
3. What shape does a barchan dune have? crescent-shaped sand dune
4. When a barchan dune comes across winds moving in two directions, incredibly long dunes can
form, which are called what? Linear dune
5. When the wind is perpendicular to the crest of the dune, the dune is called what? Transverse
dune
6. As seasons change and wind blows in different directions, what type of dune will form? Star
dune
7. Which dune has a U shape and forms from unidirectional wind and the presence of vegetation?
Parabolic dune
, 8. Name three types of obstacles that can drive the formation of dunes. Vegetations, Cliffs, hills,
and manmade obstacles.
9. Match the term with its proper definition.
__C__ Complex Dune A. The most basic form of a dune.
__A__ Simple Dune B. The same type of dune superimposed onto one another. __B__
Compound Dune C. Different types of dunes overlapping one another.
10. Name three important factors that drive dune formation. Time, wind regime, and sand supply.
II. Dune Profile
Read the definitions/hints within the diagram below and use them to determine which of the
Windward (Stoss) Slope
Slipface
Previous Slip Faces
Leeward Successive slip faces created as dune migrates
Direction of Dune Movement
terms provided below should be placed in each blank box.
, III. Case study: The Disappearing Aral Sea
The Aral Sea was once the fourth largest lake in the world. Over the last several decades, the lake
decreased in size by more than 80% and the Southern (larger) Aral Sea disappeared altogether. This
disappearance had devastating effects on communities in the region.
Go to NASA’s Earth Observatory site and read the article for “Shrinking Aral Sea” at
https://www.earthobservatory.nasa.gov/world-of-change/AralSea. As you watch the timelapse clip, you
will see dramatic changes in the aerial extent of the Aral Sea.
1. When did the Aral Sea begin to shrink? What caused the Aral Sea to shrink? The Aral Sea began
to shrink in the 1960s. It was caused by the diversion of water from the Amu Darya and Syr
Darya rivers for agricultural irrigation.
2. How has the shrinking lake affected the quality of the water and farmland in the region? The
shrinking of the Aral Sea has had a devastating impact on the people and environment of the
region. The poor water quality and salinized farmland have made it difficult for people to live and
farm. As the Aral Sea has dried up, fisheries and the communities that depended on them
collapsed. The increasingly salty water became polluted with fertilizer and pesticides. The
blowing dust from the exposed lakebed, contaminated with agricultural chemicals, became a
public health hazard.
3. How has the lake’s loss affected local summer and winter temperatures? The loss of the
moderating influence of such a large body of water made winters colder and summers hotter
and drier.
Step forward in time to see changes in the Aral Sea. The green region is the lake and the white
region around the lake is the result of salt deposits. The yellow boundary around the sea is the
approximate shoreline of the Aral Sea in 1960. Utilize the scale bar in the lower right corner of the
images to approximate distances.
4. What was the distance between the eastern edge of the Aral Sea in 1960 and the western edge
of the Southern Aral Sea in 2000? Compared to 2005? Compared to the distance in 2010? And,
in 2015? The distance between the eastern edge of the Aral Sea in 1960 and the western edge of
the Southern Aral Sea decreased significantly over time, from 200 km in 2000 to 0 km by 2010.
The Southern Aral Sea remained dry in 2015. This is because the Aral Sea has been shrinking
rapidly since the 1960s due to the diversion of water from its two main tributaries, the Amu
Darya and Syr Darya rivers, for irrigation purposes.
5. What was the distance change between 2000 and 2005? Between 2005 and 2010? And,
between 2010 and 2015? Does the rate of loss appear to be accelerating? The distance change
