6.1 Introduction to the atmosphereIB Environmental Systems and Societies SL: Flashcards
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What is the atmosphere's role relative to the biosphere?
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- What is the atmosphere's role relative to the biosphere?
- It forms the boundary between Earth and space and is the outer limit of the biosphere; its composition and processes support life.
- Why is the equator heated more than the poles?
- Sunlight arrives at a steeper angle, so energy is concentrated over a smaller area, and it passes through less atmosphere.
- What does the tricellular model show?
- Three circulation cells in each hemisphere (Hadley, Ferrel, polar) that redistribute heat from the equator to the poles.
- What happens to air in the Hadley cell at the equator?
- It is heated and rises (ITCZ), cools, condenses and gives heavy rainfall.
- Why are many deserts found near 30° N and S?
- Air from the Hadley cell sinks there; sinking air warms and dries, so rain is rare.
- Name four greenhouse gases.
- Water vapour, carbon dioxide, methane and nitrous oxide (N2O).
- What is black carbon?
- An aerosol of soot particles from incomplete combustion that absorbs sunlight and infrared radiation.
- How does black carbon on snow speed up melting?
- It darkens the surface and lowers albedo, so more solar energy is absorbed.
- Which type of radiation do greenhouse gases absorb and re-emit?
- Infrared (long-wave) radiation emitted from the Earth's surface.
- Outline the greenhouse effect in three steps.
- Short-wave radiation warms the surface; the surface emits infrared; greenhouse gases absorb and re-emit it, some back to the surface.
- By how much does the natural greenhouse effect warm the Earth?
- About 33 °C: mean surface temperature is about 15 °C instead of about -18 °C.
- Why is Venus much hotter than Mars?
- Venus has a very dense carbon dioxide atmosphere that traps heat; Mars's atmosphere is very thin, so little heat is retained.
- Is the greenhouse effect itself harmful?
- No. The natural effect is essential for life; the problem is the enhanced effect caused by extra emissions.
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).