Physical Environment Of Tropical Desert (1A) Flashcards
What types of desert are there?
Tropical desert and temperate desert
Characteristics of tropical desert
Tropical desert is located near the Tropic of Cancer (23N) and Tropic of Capricorn (23S). It is hot all year, and examples are the Sahara desert, Arabian desert, Thar desert, Somali desert, Kalahari desert, Namib desert, Great Australian desert, Mojave desert and Atacama desert.
Characteristics of temperate desert
Temperate desert is located at higher latitudes (40N/40S). Winters in those desert are cold. Examples are Turkestan desert, Takla Makan desert, Gobi desert, Great Basin desert and Patagonian desert
Example of tropical desert
Sahara desert, Arabian desert, Thar desert, Somali desert, Kalahari desert, Namib desert, Great Australian desert, Mojave desert and Atacama desert
Example of temperate desert
Turkestan desert, Takla Makan desert, Gobi desert, Great Basin desert, Patagonian desert
Climate characteristics of all desert
- Scarce and unreliable rainfall
- the annual rainfall is scarce in deserts. There is rain for a few months in desert. Rain is irregular and unpredictable, there may not be rain for a few months or even years. But when rain comes, it will rain heavily ver a short time. - High evaporation rate
- in desert, the evaporation rate is high. Sometimes the rainwater evaporates shortly in the air and never reaches the ground. - Large daily range of temperature
- the mean daily range of temperature is large. This is because clouds are rare in deserts, In the daytime, the land heats up quickly and at night, it loses heat quickly too.
Rainfall of desert
The annual rainfall in desert is scarce. There is rain for a few months. Rain is irregular and unpredictable in desert, and sometimes there won’t be any rain for a few months or even years. When rain comes, it falls heavily over a short time.
Evaporation rate in desert
The evaporation rate in desert is high. Sometimes, the rainwater evaporates shortly in the air and never reaches the ground.
Daily range in temperature in desert
Deserts have a large daily range in temperature. It’s because clouds are rare in desert. Therefore, in the daytime, the land heats up quickly, and at night time, the land loses heat quickly.
Clouds affection in different places VS in desert at night
Clouds absorb heat, so at night, cloud will release heat, and the release heat will be absorbed by land, so the land will be releasing and absorbing heat at the same time. So in places with clouds regularly, at night time, the places loses heat slower than desert.
Formation of convection rain
Convection rain is formed when the sun intensely heats the earth’s surface. Air expands and rises. The air temperature then falls, and the relative humidity increases. Water is saturated in the air at dew point, and due to condensation, the water vapour condenses into clouds. The air continues to rise due to the released heat. Strong convection currents and thick clouds are created. The water droplets in the clouds become heavy enough to fall as convection rain.
Characteristics of convection rain
- They often occur in continental and tropical regions during the summer
- They usually occur in late afternoon when the convection current is the strongest
- The duration of the convection rain is short
- They are commonly accompanied with thunderstorm
Convection rain occur in a place’s starting reasons
- The place has intense direct heat
- High temperature
(Sufficient to create convectional rainfall / convection rain)
Surface material characteristics of desert
Desert’s surface is made out of more than one materials, just like Sahara desert, it is made out of rocky, stony and sandy areas. Soils in desert are often dry, thin, sandy, salty due to evaporation rate higher than rainfall, and lack of organic matter, which leads to desert not being able to support dense vegetation
Surface material types of desert
Rocky desert:
Have barren rock surface made out of large rocks
Stony desert:
Covered with broken pieces of stones
Sandy desert:
Covered with sand made out of sand dunes and large area of sands
Vegetation starting point for desert
The air is dry in desert because the relative humidity in the desert is low. The low annual rainfall means there is an insufficient rain for vegetation growth. The dryness in the desert then results in a low vegetation cover
Vegetation type found in the desert
Desert landscapes are usually barren lands with very small amount of vegetation. Very few plant can grow in the desert because they need more water to survive. Short, rough shrubs and short trees can be found in desert because they need less water to survive.
How does cactus survive in the desert?
- Their spines help them lessen down the water loss from transpiration and help protect the cactus from thirsty animals
- Their waxy skins help them reduce the water loss from transpiration due to their thick skin. They also help the cactus to store water
- The large, thick, fleshy stems act as water storage
- Their shallow roots help to absorb water immediately after rain.
How does acacia tree survive in the desert?
- The wild root network helps absorb water from the surface of the soil
- The small leaves reduce the surface area from water loss.
How does the rose of Jericho survive in the desert?
- Dormant seeds can propagate and wait until the correct condition to grow
- They can dry to retain 3% of their body mass, so they can maintain itself in very low rainfall and moisture areas. They can also live for 3 years without water.
