component one : topic one Flashcards
what is the global circulation system?
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the global circulation system is the transfer of heat around the earth.
what is the pressure like in arid areas?
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the pressure in arid areas is high.
what is an arid area?
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an arid area receives little to no precipitation.
what is the pressure like in high rainfall areas?
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in high rainfall areas, the pressure is low.
describe the three step process of the global circulation system:
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- ) firstly, warm air rises at the equator, which is a low pressure area (so receives a high amount of rainfall).
- ) then, the cool air falls at 30° north or south of the equator, making a high pressure area (which receives little to no precipitation).
- ) finally, as the air falls, it warms again and flows back to the equator to complete the cycle.
what do ocean currents do?
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ocean currents also transfer heat around the globe.
explain two different ways that ocean currents are powered:
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- ) one way ocean currents are powered is by wind, resulting from the atmospheric circulation cells.
- ) secondly, ocean currents can be powered by density differences (due to differences is water temperatures, the denser cold water falls as the warmer water rises). differences in salt concentration (or salinity), the saltier water falls and the less concentrated water rises.
where is the sun’s UV heat energy most intense?
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the sun’s UV heat energy is most intense at the equator, making it warmer.
what happens where circulation cells meet?
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where circulation cells meet, the sun’s UV heat energy is transferred.
where does warm air rise from and to?
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warm air rises from the equator to 30° north or south of the equator in the Hadley Cell.
which cell carries hot air from the equator to 30° north or south and back?
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the Hadley Cell carries hot air from the equator to 30° north or south where it cools and returns to the equator as part of the global circulation system.
what happens to the air pressure and precipitation patterns when warm air rises at the equator?
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when hot air is rising, an area of low pressure is created. the rising air cannot hold as much moisture, so precipitation is very high at the equator.
what happens to the air pressure and precipitation patterns when cool air falls at 30° of latitude north and south?
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when cool air falls at 30° north or south of the equator, it creates areas of high pressure. this air can hold more moisture so precipitation levels are low (arid) at the Tropics of Cancer and Capricorn (30° north and south).
explain five natural causes of climate change:
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- ) natural climate change can be caused by a small change in the Earth’s orbit every 100,000 years. these are known as Milankovitch cycles.
- ) natural climate change can be caused by a change in the amount of energy emitted from the Sun. this changes of an eleven year cycle.
- ) natural climate change can be caused by volcanic eruptions which release ash dust into the atmosphere. these particulates absorb and reflect the Sun’s energy which can cause global dimming, a change in rainfall patterns and a cooling effect.
- ) natural climate change can be cause by large asteroid collisions, the materials released into the atmosphere after the collision block out the sun. also, asteroids hitting the earth can cause large fires, which emit high amounts of carbon dioxide (a greenhouse gas) which leads to the greenhouse effect, and subsequently global warming.
- ) natural climate change can be caused by a change in ocean current. this effects the way heat is transferred around the globe, so can cause global warming and cooling.
give a fact about global temperatures to support the existence of global warming:
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global temperatures are rising, for example the average global temperature is 1° higher than the average global temperature in 1900.
give a fact about carbon dioxide levels to support the existence of global warming:
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atmospheric carbon dioxide levels are increasing in parallel to a rise in global temperature.
give a fact about ocean temperatures to support the existence of global warming:
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ocean temperatures have risen by 0.1°C per decade since 1970.
give a fact about sea levels to support the existence of global warming:
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sea levels rose by 14cm during the 20th century.
give a fact about arctic sea ice to support the existence of global warming:
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arctic sea ice covers 13cm less each decade.
give three key features of a tropical cyclone:
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- ) they have a low pressure - very warm, moist air rises through the atmosphere, sucking more air up behind it.
- ) they rotate - the Earth’s spin, known as the Coriolis effect helps this rising air to spiral, which drags in strong winds. at the equator, the Coriolis effect is weak here, so no tropical cyclones form.
- ) tropical cyclones form a cylinder shape - tropical cyclones are a cylinder of rising, (low pressure created) spiraling air which surrounds the eye of descending air (high pressure created).
describe the movement of a tropical cyclone:
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tropical cyclones begin in the tropics where the water is warm. then they move westward because strong winds from the east around the equator cause the cyclone to spin away from the equator (this means that tropical cyclones can never form at the equator because of the winds. tropical cyclones can travel 640km in one day.
what three things make a tropical cyclone intensify?
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- ) low wind shear - so the wind comes from one direction allowing a cyclone to form.
- ) high humidity - there needs to be moisture in the air
- ) warm water, over 26.5°C to give the cyclone energy.
what three things make a tropical cyclone dissipate?
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- ) reach land and lose energy from the water.
- ) moving into cold water - same as above.
- ) high wind shears that damage its structure.
what is the strongest and most damaging category of tropical cyclones?
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category five has the greatest wind speed (252km/hour plus), greatest storm surges (5.7m plus) and the greatest damage.