OCR Geography -Hot Deserts Flashcard

where are hot deserts found ?
where are hot deserts found ?
30 degrees north and south of the equator.
(tropic’s of Capricorn and cancer)
Describe hot desert climates ?
Describe hot desert climates ?
-40 degrees (+) in daytime
-Cooler at night
-less than 250 mm of rain per year
-High wind speeds
-lack of cloud cover because there is no cloud cover
-High pressure
What is meant by weather ?
What is meant by weather ?
what is happening in the atmosphere around us at any moment.
What is meant by climate ?
The average weather over several years.
What is a desert ?
What is a desert ?
A place that receives less than 250 mm of precipitation per year.
What is a trade wind desert ?
The trade winds blow from sub-tropical areas with high pressure towards the equator where there is low pressure they are dry winds e.g. Sahara
What causes coastal deserts ?
What causes coastal deserts ?
Cold ocean currents near the coast cools the air so I doesn’t rise and there is no rain.
cold air sometimes causes mist or fog at sea level
e.g. Namibia
What causes Rain-shadow deserts ?
What causes Rain-shadow deserts ?
-when wind blows across a mountain range the air loses moisture.
-It creates a rain shadow on the leeward side
e.g. Atacama
What causes Monsoon deserts ?
-Monsoon winds are seasonal winds in Asia
-South-West monsoons bring rain that falls mostly falls on the Himalayas
-North-East monsoons bring dry weather
-e.g. Thar
Where is the Sahara Desert ?
Where is the Sahara Desert ?
North Africa
Where is the Australian Desert ?
Central Australia
Where is the Kalahari Desert ?
South West Africa
Where is the Thar Desert ?
Where is the Thar Desert ?
North West of India
Where is the Atacama Desert ?
Where is the Atacama Desert ?
North west of south America (Chile )
where is the Mojave Desert ?
West of North America
what is diurnal range ?
The difference in temperature between night and day
What is a sand dune ?
What is a sand dune ?
-Sand dune is a pile of sand that can be 30 meters high.
-Semi circle shaped
-They have a very steep side and a less steep side
-Wave pattern
what is saltation ?
what is saltation ?
-Sand moves like a leap frog movement
-Moved by the wind near to the ground
What is a Wadi ? How are they formed ?
A gully formed by flash floods
What is a Yardang ? How are they formed ?
What is a Yardang ? How are they formed ?
– Narrow steep sided ridge
-The troughs are created by less resistant rock being eroded away by wind
-The more resistant rock isn’t eroded
What is a Rock pedestal ? How are they formed ?
What is a Rock pedestal ? How are they formed ?
-when wind blown sand has eroded away the less resistant rock by abrasion.
What is a Canyon ? How are they formed ?
What is a Canyon ? How are they formed ?
-deep,steep sided valley
-Eroded by water
What is a Salt pan ?
Dried out salt lake with a crusty salt surface.
What are mesa's and Butte's ? How are they formed ?
What are mesa’s and Butte’s ? How are they formed ?
Butte= small isolated ,flat topped mountain
formed but freeze thaw weathering scree at bottom
Mesa= flat topped mountain with steep sides (lager than butte) wider than is is tall.
What is weathering ?
What is weathering ?
The disintegration and decay of rocks.
What is Erosion ?
What is Erosion ?
The warring away of rocks.
What is Deposition ?
The laying down of material that has been eroded.
what is meant by strata ?
The layers of rock.
what is scree?
what is scree?
lose stones
What is an ecosystem?
A geographical area where organisms,weather and land scape work together.
Every factor depends on every other factor either directly or indirectly
What is an Xerophyte ?
What is an Xerophyte ?
They have characteristics which enable them to survive in the desert
– e.g. cactus
What is an ephemeral ?
What is an ephemeral ?
Organisms that complete their life cycles in weeks or months rather than years
What is a food chain ?
What is a food chain ?
A series of organisms each dependent on the next as a source of food
What are the causes of desertification ?
-Drought
-Climate getting hotter
-Growing population = more food needing to been grown
-Deforestation =soil is being blown away
What are the consequences of desertification ?
What are the consequences of desertification ?
-Ground is left very dry
-Useless for farming
-Less food can be produced
-Lack of soil
What are the solutions to desertification ?
– Sustainable farming
-Stop over grazing to let ground recover
-Plant trees to keep soil in place
-Irrigate soil so it is wet
What are benefits of tourism in the desert ?
What are benefits of tourism in the desert ?
-Creates jobs
-Improves lives for locals – more money =better housing,education, better food.

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