Chapter 2 - Hot Deserts systems and landscapes

Question 1

What is an arid environment?

Answer 1

• The Climate of an area that receives less than 250 mm of precipitation per year.

Question 2

What is the aridity index?

Answer 2

• The ratio between precipitation (P) and potential evapotranspiration (PET).

Question 3

What is continentality?

Answer 3

• The impact of increasing distance form the coast on the climate of an area.

Question 4

What is a desert?

Answer 4

• An arid environment receiving very low levels of rainfall.

Question 5

What is a semi-arid environment?

Answer 5

• The climate of an area that receives between 250 and 500 mm of precipitation per year.

Question 6

What is the water balance?

Answer 6

• The relationship between the annual precipitation received and the amount of water lost to potential evapotranspiration.

Question 7

What is an abrasion?

Answer 7

• Where material carried by moving wind of water hits exposed rock surfaces, thus wearing the away. Known as the sandblasting effect or sandpaper effect.

Question 8

What is chemical weathering?

Answer 8

• The processes leading to the decomposition or breaking down of rocks due to chemical reactions. This most often requires the presence of water, and /or exposure to the air.

Question 9

What is deflation?

Answer 9

• Where wind removes dry, unconsolidated (loose) sand, silt, and clay particles from the surface and transports them away.

Question 10

What is a deposition?

Answer 10

• This occurs when the velocity of the wind decreases until it can no longer transport the grains it is carrying.

Question 11

What are endorheic streams?

Answer 11

• Where rivers occupy drainage basins that are closed and do not flow out to the sea or other river but instead end inland in lakes or swamps.

Question 12

What is erosion?

Answer 12

• The wearing away of the Earth’s surface by the mechanical action of processes of glaciers, wind, rivers, marine waves, and wind.

Question 13

What is exfoliation?

Answer 13

• A process of mechanical weathering that results in the breaking, splitting, or peeling-off of the outer rock layers. Also commonly known as ‘onion skin weathering’.

Question 14

What are exogenous streams?

Answer 14

• Rivers that originate external to the desert in adjacent highlands and more humid environment, flow from outside of the desert and pass through it.

Question 15

What is isolation?

Answer 15

• The incoming solar radiation that reaches the Earth’s surface.

Question 16

What is mass movement?

Answer 16

• The movement of material downhill under the influence of gravity, but may also be assisted by rainfall.

Question 17

What is saltation?

Answer 17

• A process where sand-sized particles are transported by bouncing and hopping along the surface.

Question 18

What is sediment?

Answer 18

• Any naturally occurring material that has been broken down by the processes of erosion and weathering and has then been transported and subsequently deposited by the action of ice, wind, or water.

Question 19

What is surface creep?

Answer 19

• Where saltating particles return to the surface and hit larger particles that are too heavy to hop.

Question 20

What is suspension?

Answer 20

• Transportation by wind where the smallest particles, generally less than 0.2 millimeters, are held in the air.

Question 21

What is a thermal fracture?

Answer 21

• The weathering of rock resulting from their rapid and repeated heating and cooling.

Question 22

What is transportation?

Answer 22

• The processes that move material from the site where erosion took place to the site of deposition.

Question 23

What weathering?

Answer 23

• The breakdown and/or decay of rock at or near the Earth’s surface creating regolith that remains in situ and until it is moved by later erosional processes. Weathering can be mechanical, biological/ organic, or chemical.

Question 24

What characteristics make up an Arabian desert?

Answer 24

• Almost entirely sandy, with some of the largest sand dune system in the world.

Question 25

What is an Australian desert?

Answer 25

• Mostly sandy plains.

- Mostly stony surfaces

Question 26

What is the Chihuahuan desert?

Answer 26

• High flat plateau with some stony surfaces and sandy soil, broken by mountain ranges and distinctive mesas.

Question 27

What characteristics makeup Kalahari desert?

Answer 27

• Extensive sand dunes interspersed with gravel plains.

Question 28

What makes up Mojave desert?

Answer 28

• A varied landscape including sandy soils, gravel pavements, and salt flats.

Question 29

What makes up the Sahara desert?

Answer 29

• Vast ranges of dunes amongst mountains and rocky areas, and gravel plains and salt flats.

Question 30

What characteristics make up the Thar?

Answer 30

• Mostly sand dunes with areas of gravel plains.

Question 31

What is desertification?

Answer 31

• The persistent degradation of dryland ecosystems by human activities and by climate change.