Weather & Climate Flashcards
What is inside and outside a Stevenson Screen?
Inside - Thermometer (Max. / Min.) - Hygrometer - Barometer Outside - Rain Gauge - Anemometer - Wind Vane
What are the design features of a Stevenson Screen and why?
- Above ground level: Doesn’t receive heat from ground
- White: Reflects solar radiation
- Away from buildings: Avoids heat or shadows
- Slats: Allow air circulation
- On grass: Doesn’t reflect sun’s heat much
Barometer
Measures air pressure (in millibars)
Max. / Min. Thermometer
Records maximum and minimum temperature of each day
Contains mercury and alcohol
Hygrometer
A.K.A. Wet/Dry Bulb Thermometer
Measures air humidity (% of water in air)
Has a wet and dry thermometer
Humidity is calculated using the difference between the two
Rain Gauge
Measures rainfall (mm) Placed on grass
Wind Vane
Shows wind direction
Wind is measure in the direction it is coming FROM
Anemometer
Measures wind speed (km/h or miles/h or m/s)
Placed on top of buildings
Cloud Cover
Divided mirror
Each section with parts of cloud reflected is counted, giving a percentage cover
Cloud cover can be measured in oktas
Sunshine Recorder
Measures sunshine (minutes) Sun's rays pass through a glass ball and burn a piece of path showing the sun's position
Why does the equatorial climate experience frequent thunderstorms?
- Warm air converges at the equator and is further heated by the sun
- It rises and creates low pressure below
- Causes heavy rainfall
How does the Hadley Cell work?
1) More solar radiation at the equator causes air to heat up and rise
2) Air cools and condenses
3) Air is pushed out to the sides
4) Air cools and sinks, creating high pressure
5) The density gradient between there and equator causes trade winds
Define weather.
The short-term changes and state of the atmosphere in regards to temperature, cloud cover, wind speed, precipitation, humidity, etc.
Tropical Climate
- Location
- Example
- Seasons
- Weather
- Between 5* and 15* north and south of the equator
- Brazilian Highlands
- Alternating wet and dry season due to sun’s movement
- Hot and wet when sun is overhead (like equatorial climate)
- Warm and dry when sun is at other Tropic (like desert climate)
Desert climate
- Location
- Example
- Seasons
- Weather
- During day up to 50, in the night up to 0
- Sahara desert
- Less than 250mm of rain a year
- Prescence of high pressure, creates cloud-free conditions
Define climate.
The average weather and conditions that a region or country experiences over a number of years.
What is an ecosystem?
A natural system in which the life cycles of plants and animals are closely linked to each other and to the non-living environment.
What is a biome?
An ecosystem, such as the tropical rainforest, occuring at a global scale
What are the layers of the rainforest?
Emergent Canopy Under canopy Shrub layer Ground layer
What percentage of sunlight reaches the floor of the forest?
1%
How many different species of tree are there in the rainforest?
Over 1000
Give an example of fauna that is adapted to the rainforest
Primates(monkeys + apes) - Long arms to help them swing. Some are no teens so they have large eyes to let light in, and they have long fingers to scoop at insects.
Birds (Toucan) - Long beak for reaching food
Give an example of flora that is adapted to the rainforest
Fan palms - Large, fan shaped leaves that are good for catching sunshine and water. Leaves are segmented so excess water can drain away.
Lianas - Woody vines that start at ground level and climb up trees to the canopy, where they spread from tree to tree to get as much light as possible.
What are the causes of deforestation in the rainforest?
Farming
Transport
Resources
Settlement
Describe how farming is a cause for deforestation
- Land is cleared for 3 types of farming
- ‘Slash and Burn, traditional method it causes considerable areas to be cleared
- Subsistence farming - it has increased due to government giving land to Brazil’s 25 million landless people. 10km strips of land were cleared
- Commercial cattle ranching - run by large transnational companies that sell beef to fast-food chains. They burn down the press snd replace trees with grass
Describe how transport is a cause for deforestation
- Over 12,000km of new roads built across the rainforest
- Built to develop region and to transport timber, minerals, farm produce and people
- Largest road is 5300km Trans-Amazonian highway
- 900km railway built from Carajas to the coast
Describe how resources are a cause for deforestation
Timber - obtained by logging companies, which fell trees for markets in developed countries. Little attempt made to replant deforested areas
Minerals - such as iron ore, bauxite,manganese, diamonds, gold and silver
Hydro-elcetricity - building of dams and creation of lakes has led to large areas of forest being flooded
Describe how settlement is a cause for deforestation
- Development of Amazonia has led to an increase in population from 2 million(1960) to over 30 million (2000)
- Large tracts of forest have been cleared for development of settlement such as Maraba or Carajas
How does deforestation affect the ecosystem?
28 million of the worlds 30 million known species can be found in the rainforest. Due to deforestation many of their habitats are destroyed. We get over half our medicines from the rainforest
How does deforestation affect the people?
- There has been huge reduction in the number of Amerindians
- It has fine form 6 million to the present number of 200,000
- Their traditional culture and way of life has been destroyed
How does deforestation affect the climate?
- Less evapotranspiration, so less water vapour in the air. With less moisture in the water cycle there is already evidence of reduced rainfall totals with possible increase of droughts
- The burning of the forest is accelerating global warming by releasing huge amounts of Carbon Dioxide
How is a cactus adapted to the desert?
- Long taproots to the reach groundwater
- Stems that can store water
- Widespread root system
- Spines instead of leaves ~ minimum surface area and to reduce water loss by transpiration
- Spines to protect Cacti from animals that might eat them
How does deforestation affect the world?
- No canopy to protect the soil form heavy rain, roots to bind it together.Less interception, infiltration and more surface runoff
- Deforestation breaks the humus cycle and existing nutrients are rapidly washed out of the soil leaving it infertile
- This has caused the new subsistence farming to be abandoned
- Many rivers have been polluted due to mining operations
How is a camel adapted to the desert?
- Large, flat,fleet ~ to spread their weight on the sand
- Thick fur ~ for shade, thin fur elsewhere to allow easy heat loss
- Large surface area to volume ratio ~ maximise heat loss
- Able to go for a long time without water
- Slit like nostrils and two rows of eyelashes to keep out sand
Where is the Sahel?
The Sahel is a narrow strip of land, just south of the Sahara desert. It spans 5,400Km. It covers ; Ehtiopia,Sudan,Chad,Niger,Somalia,Mali
What are the six main types of clouds?
- Cirrus
- Stratus
- Cumulus
- Alto
- Nimbus
- Altostratus
Explain the meaning of a cumulus cloud
Heap of cloud, cotton ball cloud
Explain the meaning of a stratus cloud
Layer or sheet of cloud
Explain the meaning of a cirrus cloud
Curl of hair, wispy
Explain the meaning of a alto cloud
Medium height clouds
Explain the meaning of a nimbus cloud
Rain clouds
Explain the meaning of a altostratus
Mid-height layer cloud
How do clouds form?
Water vapour rises, and when it reaches the dew point it then condenses.
Since a cloud forms at a certain dew point, what changes on a hot or cold day?
On a cold day clouds will occur at a lower place than a warm day
Describe the nutrient cycle
- Trees shed leaves all year round
- Decaying vegetation decomposes rapidly
- Nutrients enter the soil
- Shallow roots take up the nutrients
- Trees grow rapidly
What are the features of soil in rain forests?
- Shallow
- Acidic
- Iron oxide stains the top levels red
- Infertile and one of the poorest soils in the world
What happens to soil in the rain forest after heavy rainfall?
Washes away nutrients
How do plants survive in the rain forests without a good source of nutrients in the soil?
- Plant and animals quickly decay because of the humid, warm climate
- Shallow roots trees quickly absorbs nutrients
- Few nutrients are lost form the nutrient cycle
- Most nutrients are stored by the vegetation
What do people do to protect the rain forest?
- Satellite monitoring
- Tree census
- Environment Ministry
- Local Sustainable Projects
- The Rainforest Alliance
How is satellite monitoring used to protect the rainforest?
Spot deforestation occurring and try to prevent it by notifying the rangers.
Linked to the fact that deforestation has slowed by 75% by 2004
How is a tree census used to protect the rainforest?
Mark trees with numbers, therefore authorities know which trees have been cut down and can track them to find the criminals cutting them down
What is the technique used by local subsistence farmers?
Slash and burn
How are local sustainable projects used to protect the rainforest?
This stops people slash and burning.
People instead do things like make rubber bags by natural and traditional methods. They also use naturally fallen trees for their woodwork
How are the Rainforest Alliance protecting the rainforest?
Clear land in a controlled way for business
Faming is done in a responsible way
Controlling tourism
What abbreviation denotes the characteristics of a desert ecosystem?
HOMR
What does the H in HOMR stand for?
Hadley Cell
How does the hadley cell affect the characteristics of a desert?
- NE and SE trade winds converge
- Causes warm air, due to heat, to rise at the equator
- The air moves pole ward and it condenses over the rainforests
- The air then descends on the deserts, and very dry
- Low humidity and little surface water gives clear skies and a lack of rain
What does the O in HOMR stand for?
Ocean Currents
How do ocean currents affect the characteristics of a desert?
- Around the tropics are cold ocean currents
- Air is colder over ocean than land
- Cold air holds less moisture than warm air
- Cool air blows onshore, contains little vapour. Causing very arid conditions
What does the M in HOMR stand for?
Mid-Contententality Affect
How does the Mid-Contententality affect the characteristics of a desert?
- Deserts usually are a reasonable distance from a coast
- Water that is evaporated from the oceans is precipitated on coastal areas
- By the time it reaches inland most of the moisture has been lost
What does the R in HOMR stand for?
Rainshadow affect
How does the Rainshadow affect the characteristics of a desert?
- Occurs in deserts near to large mountain regions
- Trade winds are stopped by mountains
- It forces air up, where it cools and condenses to form heavy rain
- Moisture cannot reach the western slopes so making it very dry in the desert
Name the important things that tropical rainforests give us
- Biodiversity
- Photosynthesis (20% of worlds oxygen)
- Gives nutrients to the soil (nutrient cycle)
- Agricultural products (YAM, coffee, rubber etc.)
- Home to indigenous people
Define desertification
The transformation of arable or habitable land to desert
Why does desertification occur?
Change in climate
Destructive land use
Name the physical factors that contribute to desertification
- Rising Temperatures (unadapted plants die-exposing land)
- Low Rainfall(land erosion)
- Flash Floods
- Wind
Name the human factors that contribute to desertification
- Population growth (land farmed intensively)
- Over grazing
- Over Cultivation
- National Parks (tribes concentrated into smaller areas)
- Deforestation
What is the distribution of rainforests
In between the tropics and mostly along the equator
What are the characteristics of soil in rainforests?
- Thin or absent humus top layer - infertile
- Very insoluble red iron oxide
- Acidic
Define a desert
An area which has less than 250 mm of rainfall per year.
Describe the distribution of deserts
Mostly lie on tropics and on large landmasses
What does ITCZ stand for?
Inter Tropical Conversion Zone
What is the ITCZ?
Where the trade winds meet, low pressure zone
