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
What are the layers of the rainforest?
Highest
Emergent
Canopy
Under canopy
Shrub layer
Lowest
Emergent layer
The tops of all the tallest trees in the rainforest
Highest layer
Canopy layer
Where the upper parts of most trees are found.
The canopy is home to most life found in the rainforest.
3rd layer.
Under Canopy
Limited sunlight + saplings wiat here for the older plants to die –> there is then a space in the canopy which they can grow into.
2nd layer in the rainforest
Shrub layer
Due to the lack of light which reaches the forest floor –> There is very little vegetation between the trees.
What causes the soil fertility in the rainforest?
Nutrients recycling.
Rainforests are home to deciduous trees, meaning they lose their leaves over time. (not seasonally though)
These leaves get decomposed by the large amount of fungi living on the forest floor.
This creates an abundance of nutrients. However, this nutrients is quickly used up or else washed away by the heavy rainfall.
How many seasons do rainforests have?
2
One wetter season and one drier season.
Why are rainforests not suited for farming?
The fertility of the soil is dependent on the nutrients cycle.
By removing the vegetation, the cycle is disrupted and the soil becomes infertile.
Plant adaptations in the rainforest
Lianas –> use other plants to grow to sunlight.
Tree trunks –> tall + thin to reach sunlight. Bark = smooth to allow water to drip down to roots easily
Butress roots –> large roots + large surface area to support large tree
Epiphytes –> Live on other plants (more sunlight). Get nutrients from air + water –> not soil.
Drip tips –> pointy tips on leaves –> water easily runs off (instead of breaking plant)
Waxy leaves –> water easily runs off.
Animal adaptations in the rainforest
Sloth –> Slow (not seen by predators), Camoflaged fur, long claws to grip onto branches
Spider monkey –> long, strong limbs to climb through trees + prehensile tail (for gripping)
Flying frog –> fully webbed hands + feet + flap of loose skin between limbs so it can glide from plant to plant
Toucan –> Long large bill to reach fruit (if branches don’t support its weight)
Poison dart frog –> poisonous + bright to warn predators (some frogs aren’t poisonous, only bright –> still a form of protection)
Weather statistics in deserts
Temperature
Up to 50C during day but 0C at night.
Rainfall = Less than 250 mm a year
Wind = Strong
Clouds = Virtually cloudless
Humidity = Low
Pressure = High
Reasons for desert formation
- Distance from oceans
- Winds blowing accross large areas of land (loses humidity)
- Low humidity + lack of evaporation
- Sparse vegetation (no transpiration)
- High air pressure
- Descending air
- Rain shadow effect
- Cold offshore currents
Examples of vegetation in the Sonoran desert + their features of survival
Saguaro cactus - Water storage, Spikes, Taproot, Ribs on plant allows for expansion when storing water
Prickly pear - Spines (reduced water loss + protection), Water storage
Palo verde - Bark = chlorophyll (can photosynthesise even when leaves dry up), deep root system, deciduous to prevent water loss
Examples of animals in the Sonoran desert + their features of survival
Gila woodpecker - Strong beaks to hollow out hole in saguaro cactus (cool in there + spines protect woodpecker from preadators)
Kangaroo rat - Nocturnal, Longer loop of henle to reabsorb as much water as possible in the kidney, Seeds they eat contain water
Causes of deforestation
Agriculture - Cleared for commercial farming (eg. palm oil/ soybeans/ cattle)
Logging - For fuel –> clear felling. Specific trees for furniture (eg. mahogany) –> selective loggin.
Road building - ccess to new settlements/mining areas etc.
Mineral extraction - eg. Gold mining in brazil
Energy development - Building of dams causes areas to be flooded –> Submerged forest = root rot = acidic water = corroding HEP turbines
Settlement / population growth - Building of houses due to overcrowded cities. (occurs in Brazil for poor people)
Impacts of deforestation in the Amazon rainforest
Soil erosion - Roots bind soil together –> without this heavy rainfall removes topsoil. Nutrients cycle also disrupted –> soil loses fertility –> area abandoned –> more rainforest cut down for agriculture.
Loss of biodiversity - Animals + plants go extinct bc rainforests = most biodiverse areas –> loss of organisms which may help produce medicinal drugs in future.
Climate change - CO2 emissions when burning trees + less CO2 absorbed. Reduces humidity in air –> increase temp + dryness bc less evaporation (endothermic)
Economic development - Tourism declines, less timber, local people = poverty bc they rely on rainforest (eg. rubber tappers who extract natural rubber from rubber trees)
Indigenous tribes threatened (exposed to diseases they don’t have immunity to + lose land + sometimes killed by loggers)
80% of deforestation = cattle ranches
Deforestation = 15% of CO2 emissions
3 species go extinct per hour
Local impacts of deforestation
Positives
- Employment
- Production of necessary raw materials
- Energy from dams created
Negatives
- Loss of biodiversity
- Tribes threatened/die
- Soil becomes infertile –> Low yield
- Bad working conditions
Global impacts of deforestation
Positives
- Raw materials created –> allows for production of certain goods
Negatives
- Loss of potential medicines
- CO2 emissions –> climate change
Ways to decrease deforestation
Monitoring - Sattelite technology to stop illegal logging
Environmental charities + raising awareness
Rubber tapping - Doesn’t hurt trees (extractive reserve farming - materials naturally growing in forests are harvested)
Afforestation - Replanting trees
Selective logging - Only rtees a certain height etc.
Quotas
Natural reserves/National parks
Eco-tourism
Amazon rainforest - Climate (7-mark question)
- Equatorial Climate
- Hot average temperature all year round
- High precipitation (over 2000mm a year)
- Hadley cell at the equator –> air heated by sun –> rises (low pressure) –> cools + condenses –> clouds + precipitation (rain)
- High levels of soil moisture + interception of rainfall from dense vegetation –> leaads to transpiration
–> Creates convectional rainfall.
(two seasons, wet + dry –> occurs when rainforests are not exactly centred on the equator (slight differences in temp + thus rainfall))
- Repetitive climate –> dry but misty mornings + late afternoon downpours and convectional
storms. (Always humid air)
(High biodiversity –> 250 species of trees per hectare
