Climate Flashcards
Where are deserts located?
Between 5 - 30 degrees north + south of the equator.
- Outside tropical areas (eg. rainforests)
- In the rainshadow of mountain ranges
- Found inland on continents
- Cold ocean currents
Climate
The weather conditions prevailing in an area in general or over a long period
How are deserts formed? (high air pressure)
- Sunlight is most direct at the equator (meaning it is the warmest)
- Warm air rises and then condenses, forming clouds.
- Colder + denser air flows poleward (away from equator)
- As it moves it precipitates and loses its humidity.
- Once cool + less dense it sinks at approx. 30 degrees north/ south of the equator –> forming high air pressure
- The air warms up again by the sun, however, it has no moisture –> leading to extremely dry + hot deserts.
How are deserts formed? (rainshadows)
- Warm moist air moves across a coastal range
- It then reaches a mountain range and is forced up (increasing altitude)
- This causes it to cool + condense + form clouds + precipitate
- Once having passed over the mountain it continues to sink (with no moisture) + heats –> forming dry + hot deserts.
How are deserts formed? (Inland on continents)
- While moving across an ocean, air picks up moisture –> humidity
- When reaching land the moist air begins condensing + precipitating (however, no new moisture is being picked up)
- Eventually all moisture is removed from the air as wind travels inwards
–> Dry + hot air formed inland –> Deserts
How are deserts formed? (Cold ocean currents)
- Cold ocen winds meet warm land air –> Mositure condenses + fog formed.
- Thus moisture is removed from air and further inland a desert is formed.
(These currents are typically found on the west side of continents)
–> Why deserts form on the west side of continents (check with Miss Kappa)
Soil of hot desert
- Little vegetation in deserts –> barely any organic matter in soil
- Weathering (bc of strong winds not hindered by vegetation) creates deep deposits of sand + loose materials
–> Sand dunes can also form. - Soil can potentially bevery fertile bc important nutrients for plant growth (eg. calcium) haven’t been used up by vegetation.
- Topsoil is often baked by sun
Climate graph
Layered graph showing both rainfall + temperature across a year
Bar chart = rainfall
Line graph = Temperature
Sonoran desert
- Hot desert
- Located in subtropical region of North America (hot summer + mild winters)
- Has many saguaro cacti
- Summer temp = usually 40C + sometimes more than 48C
- High diurnal temperature range
- 75-500mm annual rainfall
- July - mid-September = summer monsoon (thunderstorms
- Bi-seasonal rainfall
Why the Sonoran desert formed
- High pressure air
- Rainshadow effect (air blows across pacific ocean + picks up msoiture. When the air hits the mountains on the Arizona-California border it precipitates
- Cold ocean currents (california current) cause desert to be formed inthe west side of the continent
Typical plant adaptations in the desert
Small leaves - Less water lsot from plant by transpiration (bc smaller surface area.
Tap roots - Long roots (7-10 metres long) that reach deep under ground to acess water supplies –> much longer + bigger than plant visible at surface.
Spines - (instead of leaves, eg. cacti) Spines lose less water than leaves + prevent animals from eating plant
Waxy skin - Reduces water loss by transpiration
Water storage - Eg. succulents store water + have waxy skin
Typical animal adaptations in deserts
- Nocturnal (bc cooler at night)
- Burrow underground (colder)
- Big ears to keep them cool
- Light-coloured coats –> reflect sunlight
- Diet/ food contains moisture (eg. seeds) not necessary to find as much water.
Tropical rainforest location
Along the equator + inbetween the tropics
- Main areas are northern South America (e.g. Amazon), Central Africa (e.g. Congo) and South East Asia.
Tropical rainforest climate - Characteristics
- Consistently high temperatures throughout the year – an average of about 25°C
- Annual temperature range: less than 5°C
- Rainfall – amount exceeds 2000mm
- Rainfall– seasonal distribution: fairly evenly distributed throughout the year
- Wind: low
- Cloud: heavy
- Humidity: high
- Pressure: low
- Little seasonal variation
What type of rainfall do rainforests typically recieve?
- Convectional rainfall
Sun’s energy heats surface of earth –> water evaporates + expands + rises –> cools 0 condenses –> Forms (cumulonimbus) clouds