Lesson 16: Deserts and Winds Flashcards

1
Q

How are deserts defined?

A

Arid regions with average annual rainfall less than 250 mm

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2
Q

How are steppes defined?

A

Semi-arid regions that get 250-500 mm of rain annually

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3
Q

What are the different types of deserts? (6)

A
  1. Subtropical Deserts
  2. Continental/Mid-latitude Deserts
  3. Rain Shadow Deserts
  4. Coastal Deserts
  5. Monsoon Deserts
  6. Polar Deserts
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4
Q

How are Subtropical Deserts Characterized?

A

Trade winds that blow east to west, just north and south of the equator.

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5
Q

Where are Subtropical Deserts found?

A

Hoarse latitudes are centered between 20 degrees and 30 degrees North and South latitude.

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6
Q

What is an example of a Subtropical Desert?

A

Sahara Desert

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7
Q

How are Continental/Mid-latitude Deserts characterized?

A

Wide rage of annual temperatures

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8
Q

Where are Continental/Mid-latitude Deserts found?

A

Between 30 and 50 degrees N and S of the Equator in interior drainage basins far from the source of moisture.

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9
Q

What is an example of Continental/Mid-latitude Deserts?

A

Sonoran Desert in North America
Gobi and Taklamakan Deserts in Central Asia

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10
Q

How are Rain Shadow Deserts Characterized?

A

A desert formed in the lee-side “shadow” of the mountain range

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11
Q

Where are Rain Shadow Deserts found?

A

In Mountainous areas

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12
Q

Give an example of rain shadow deserts.

A

Turpan Depression in the rain shadow desert of the Tian Shan of China
Death Valley National Park, California in the rain shadow of the Sierra Nevada mountains.

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13
Q

Characterize Coastal deserts.

A

Affected by cold ocean currents that are parallel to the coast with local wind systems that dominate the trade winds

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14
Q

Where are Coastal Deserts found?

A

In the western edges of continents near the Tropics of Cancer (23.5 degrees N) and Capricorn (23.5 degrees S)

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15
Q

Give an example of a Coastal desert.

A

Atacama Desert, South America
Namib Desert, Africa

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16
Q

Characterize Monsoon deserts.

A

Wind system with pronounced seasonal reversal

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17
Q

Give an example of a Monsoon desert.

A

Thar Desert of India/Pakistan

18
Q

Characterized polar deserts.

A

Mean temperature during the warmest month of less than 10 degrees C

19
Q

Give an example of a polar desert.

A

Northern Greenland
Ice-free areas of Antarctica

20
Q

Why is mechanical weathering dominant in arid regions?

A

Chemical Weathering requires water

21
Q

What type of running water is more dominant in arid regions? (ephemeral or perennial)

A

Ephemeral

22
Q

How does wind cause erosion?

A
  1. By deflation
  2. By abrasion
23
Q

What does deflation produce?

A
  1. blowouts
  2. desert pavement
24
Q

What are blowouts?

A

Shallow depressions produced by deflation

25
Q

What is desert pavement?

A

a veneer of pebbles and cobbles

26
Q

What does abrasion create?

A
  1. ventifacts
  2. yardangs
  3. mesas and buttes
27
Q

How is sediment transported by wind?

A
  1. Bed load
  2. Suspended load
28
Q

How is bed load characterized?

A

Consists of mostly sand-sized particles

Sand moves across the surface in a process called saltation

29
Q

How is suspended load characterized?

A

Consists of mostly slit sized particles that are carried high into the atmosphere

30
Q

How can you identify an asymmetric dune’s windward and leeward slope?

A

Windward: gently inclined

Leeward: angle of repose at ~35 degrees

31
Q

What is loess?

A

large deposits of windblown dust

32
Q

What are the different types of sand dunes? (6)

A
  1. Barchan
  2. Transverse
  3. Barchanoid
  4. Longitudinal
  5. Parabolic
  6. Star
33
Q

Arid regions get ____ mm of rain per year

A

less than 250

34
Q

The world’s largest desert is ____.

A

The Sahara Desert of North Africa

35
Q

Subtropical/Trade Wind deserts lie between ____ degrees north and south

A

20 and 30

36
Q

Ephemeral streams are also called

A

wadis
washes
arroyos
nullahs

37
Q

___ does most of the erosional work in deserts.

A

Running water

38
Q

As air rises over mountain ranges, water is precipitated and the air loses its moisture content. As a result, a desert is formed in the ____ “shadow” of the range.

A

leeward

39
Q

The suspended load (wind) consistes mostly of ____ -sized particles.

A

silt

40
Q

___ is the lifting and removal of loose material by the wind.

A

Deflation

41
Q

___ are stones that are shaped and polished by wind abrasion

A

ventifacts