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Topic 2 of 6 · Form 5

Atmosphere and weather

Diurnal energy budget (incoming solar radiation, reflected solar, surface absorption, long-wave radiation, sensible and latent heat transfer); the global energy budget and latitudinal imbalance.

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  1. PDFAtmosphere and weather – Geography notes (Cambridge A Level)45.6 KB

Energy budgets

Diurnal energy budget (incoming solar radiation, reflected solar, surface absorption, long-wave radiation, sensible and latent heat transfer); the global energy budget and latitudinal imbalance.

Atmospheric circulation

Pressure belts and winds; the tricellular model (Hadley, Ferrel and polar cells); the ITCZ and its seasonal migration; jet streams; ocean currents.

Weather processes

Humidity, dew point, condensation, clouds and precipitation; atmospheric stability and instability (environmental and adiabatic lapse rates: DALR ≈ 9.8 °C/km, SALR ≈ 5–7 °C/km).

Worked example: Air at 30 °C rises 1.5 km unsaturated. Find its temperature.

30 − 1.5 × 9.8 = 15.3 °C

Human impact

Urban climates (heat island, pollution, wind effects); enhanced greenhouse effect and climate change.

Exam tip: Use the relationship between ELR, DALR and SALR to explain stability on a diagram.

Check yourself

  1. What is the dry adiabatic lapse rate?
  2. Why are urban areas warmer than surrounding rural areas?
  3. How does the ITCZ affect rainfall in southern Africa?
Show answers
  1. The rate at which unsaturated rising air cools – about 9.8 °C per km.
  2. Building materials store heat, fewer plants for evaporative cooling, waste heat, pollution trapping heat.
  3. Its southward movement in the southern summer brings convectional rainfall (rainy season).
Next topicRocks, weathering and tropical environments

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