Types of Deserts Flashcards
In deserts what is the main source of erosion?
Air or wind
In glaciers what is the main agent of erosion?
ice
_____ and _____ can be sensitive indicators to climate change
deserts, drylands
Deserts make up how much of Earth’s land area?
25%
What are the two criteria that a “desert” has to meet for it to be a desert?
- Must receive less then 255mm of rainfall per year
- sparsely vegetated
How do we split up, divide, or categorize deserts?
two categories:
- deserts formed by global air circulation
- deserts formed by local climate conditions
Which two types of deserts are formed based on their location on the globe (global air circulation)?
- subtropical deserts
- polar deserts
Global circulation units lead to up flows of warm and wet air at the ______
equator
bands of ______ form some of the major deserts
latitudes
Subtropical deserts are located at approximately _____ degrees North and _____ degrees South
30, 30
Where are polar deserts located?
at approximately 90 degrees North and south
Do polar deserts get a lot of snow?
no, whatever snow they get just never goes away
What 3 kinds of deserts form due to local climate conditions?
- continental interior deserts
- rain shadow deserts
- coastal deserts
_____ ______ deserts are located far inland
continental interior
e.g.
Gobi Desert, north China/ South Mongolia
Are continental interior deserts located close to a source of water?
No
Where do rain shadow deserts form?
along mountain ranges
E.g.
death valley, rain blocked by Sierra Nevada mtns
Mountain ranges serve as a _____ to block precipitation
barrier
What happens when clouds and weather systems come towards a mountain?
As clouds and weather systems come towards a mountain the steepness and height of a mountain forces that air system up and as it rises it drops a lot of it precipitation so by the time it reaches the other side of the mountain it is very dry air.
where do coastal deserts form?
along the oceans
e.g.
Atacama desert, Chile. Driest place on Earth
Do coastal deserts form along the western or eastern side of continents?
western
Coastal deserts form along the _____ side of continents because there are very cold ocean currents flowing next to the land.
western
What do cold ocean currents cause?
cold air
Cold air holds _____ moisture so there is ____ precipitation
less, little.
Where is the Atacama desert?
in South America, along the Andes mountains
As clouds and weather systems come towards a mountain the ______ and _____ of a mountain forces that air system up.
steepness, height
As clouds and weather systems rises they drop a lot of _______ so by the time the system reaches the other side of the mountain there is very _____ air.
precipitation, dry
Are deserts and glaciers rare or common environments?
rare
Why are deserts and glaciers rare environments?
because water is not the main erosional force, air and ice are
Deserts and Glaciers are two types of _____ environments
rare
Deserts and Glaciers are two rare types of environments where _____ is not the main erosional force, but _____ is.
water, air/wind
On the Earth there are very general ____ ____ ___ of air in the atmosphere
global circulation units
Global circulation units lead to upflows of ____ and ____ air at the equator
warm, wet
______ of warm and wet air flow away from the equator
upflows
What direction do upflows flow?
north to south in a cyclic motion (circulate)
Where are subtropical deserts located?
At about 30 degrees north and south
What are two examples of subtropical desert?
Namibia and Sahara desert
The ______ desert is the largest subtropical desert
Sahara
Where are polar deserts located?
- At 90 degrees north and south
- near the poles
Continental Interior Deserts become deserts simply because there is no local source of ______ to bring precipitation.
water
By the time winds and air circulation reach areas deemed as Continental Interior Deserts, all of the _______ has been dropped, so there is none left to water these areas.
precipitation
Mountain ranges serve as a _____ to block precipitation from reaching areas
barrier.
The area on the other side of a mountain that does not receive a lot of precipitation could become a _______ desert.
rainshadow
______ deserts form where there is cold ocean currents next to the land
Coastal
Where do Coastal deserts form?
- where there is cold ocean currents - along western edges of continents where there is very cold ocean currents flowing near the land
Because cold air can’t hold very much ______ so there is not a lot of moisture forming along coastal desert areas.
moisture
The cold ocean currents create ____ air above the ocean
cold
