6.1 Introduction to the atmosphereIB Environmental Systems and Societies HL: Flashcards
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Why does the equator receive more energy per unit area than the poles?
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- Why does the equator receive more energy per unit area than the poles?
- Rays strike at a steeper angle, concentrating energy over a smaller area and passing through less atmosphere.
- What does the tricellular model do?
- Redistributes heat from the equator towards the poles through Hadley, Ferrel and polar cells.
- Why is the Atacama Desert dry?
- It lies under the descending Hadley cell, where sinking air warms and dries.
- Name four greenhouse gases and one aerosol.
- Water vapour, carbon dioxide, methane, nitrous oxide; black carbon.
- How does the greenhouse effect work?
- Short-wave radiation warms the surface; infrared radiation emitted is absorbed and re-emitted by GHGs, some back to the surface.
- What is the GWP of methane?
- About 28 over 100 years: tonne for tonne it warms 28 times as much as CO2.
- (HL) Why is the atmosphere a dynamic system?
- Its layers and composition result from continuous physical and chemical processes.
- (HL) Why does the atmosphere thin with altitude?
- Gravity pulls molecules towards the surface and weakens with distance, so density and pressure fall.
- (HL) What are Milankovitch cycles?
- Regular changes in orbit shape, axial tilt and wobble that change the solar radiation reaching Earth.
- (HL) Give the time scales of the three Milankovitch cycles.
- Eccentricity about 100 000 years, obliquity about 41 000, precession about 21 000 to 23 000.
- (HL) What has characterised the Quaternary climate?
- Repeated glacial and interglacial cycles.
- (HL) How is global warming different from Milankovitch cycles?
- It is rapid and caused by greenhouse gases, moving the Earth away from the glacial-interglacial cycle to hotter conditions.
- (HL) How did cyanobacteria change the atmosphere?
- They released oxygen through photosynthesis and removed carbon dioxide, raising oxygen after about 2.4 billion years ago.
- (HL) How did more oxygen influence evolution?
- It enabled aerobic respiration and larger organisms, and formed the ozone layer so life could colonise land.
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).