The Processes That Shape Our Weather and Climate

What The Processes That Shape Our Weather and Climate covers

The processes that shape our weather and climate is examined in Unit AS 1, Physical Geography. It covers the global energy balance, vertical and horizontal heat transfer in the atmosphere, ocean currents and the transfer of heat, pressure belts, the Coriolis effect and the pressure gradient, the tri-cellular model, the global winds, and where it breaks down, jet streams and the upper westerly winds, global patterns of temperature, pressure, wind and precipitation and factors influencing air temperature.

The 8 subtopics

Each one has its own page.

• The global energy balanceGlobal energy balance, earth's planetary albedo and double role that clouds play in the energy balance.Open →
• Vertical and horizontal heat transfer in the atmosphereVertical and horizontal heat transfer in the atmosphere and how convection transfers heat upwards.Open →
• Ocean currents and the transfer of heatUpwelling and why does it matter for the fishing industry, thermohaline circulation and what a world map of ocean currents would show.Open →
• Pressure belts, the Coriolis effect and the pressure gradientConditions found in the equatorial low pressure belt, conditions found in the subtropical high pressure belt and conditions found in the sub-polar low pressure belt.Open →
• The tri-cellular model, the global winds, and where it breaks downHadley cell, ferrel cell and polar cell.Open →
• Jet streams and the upper westerly windsUpper westerly winds, jet stream and rossby waves.Open →
• Global patterns of temperature, pressure, wind and precipitationGlobal pattern of annual precipitation, belt of very heavy rainfall along the equator and why precipitation totals rise again through the mid-latitudes.Open →
• Factors influencing air temperatureMain factors that determine the air temperature of a place, how latitude influences air temperature and why air temperature falls with altitude.Open →

What you need to know

Answer each one before you reveal it.

Take The Processes That Shape Our Weather and Climate further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Insolation vs Albedo

  Insolation: the incoming solar radiation a surface receives. Albedo: the proportion of that radiation a surface reflects back.

• Hadley cell vs Ferrel cell

  Hadley cell: a direct circulation driven by heating at the equator. Ferrel cell: an indirect circulation driven by the two cells on either side of it.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is meant by the global energy balance?

   Model answer

   Over the planet as a whole, and averaged over a year, the energy the Earth receives as incoming short-wave solar radiation is equalled by the energy it loses back to space as reflected short-wave radiation plus outgoing long-wave terrestrial radiation. Because input equals output, average global temperature stays roughly constant. The balance only holds for the planet as a whole: individual latitudes are in surplus or deficit.

2. 2

   Why does a square metre of ground at the equator receive far more solar energy than a square metre near the poles?

   Model answer

   Near the equator the sun is high overhead, so a beam of a given width strikes a small area and its energy is concentrated. At high latitudes the same beam hits the curved surface obliquely and is spread over a much larger area, so each square metre receives less. The oblique beam also travels through a greater thickness of atmosphere, so more of it is scattered, absorbed and reflected before it arrives. High latitudes also have snow and ice cover, which reflects much of what does arrive.

3. 3

   What is albedo?

   Model answer

   Albedo is the proportion of incoming short-wave radiation that a surface reflects rather than absorbs, usually expressed as a percentage. A high-albedo surface reflects most of the energy and stays cool; a low-albedo surface absorbs most of it and warms.

4. 4

   Give approximate albedo values for fresh snow, thick cloud, desert sand, forest and open ocean.

   Model answer

   Fresh snow reflects about 80-90 per cent; thick cloud about 70-80 per cent; desert sand about 25-40 per cent; forest about 10-15 per cent; a calm open ocean with the sun high about 6-10 per cent. This is why ice-covered polar regions absorb so little and why oceans absorb so much.

5. 5

   What is the Earth's planetary albedo, and where does the rest of the incoming radiation go?

   Model answer

   Roughly 30 per cent of incoming solar radiation is reflected straight back to space by clouds, the atmosphere and bright surfaces such as ice; that is the planetary albedo. The remaining 70 per cent is absorbed: about 20 per cent of the incoming total within the atmosphere itself, mainly by ozone, water vapour, dust and cloud droplets, and about 50 per cent of the incoming total by the land and sea surface.

6. 6

   Between which latitudes is there a net radiation surplus, and where is there a net deficit?

   Model answer

   There is a net surplus, with more energy received than lost, between roughly 35 degrees North and 35 degrees South. Poleward of about 35 degrees in each hemisphere there is a net deficit, with more energy radiated away than received. The deficit grows steadily towards each pole.

What is inside Levo

Six ways to work the same material.

The Processes That Shape Our Weather and Climate revision questions

What does The Processes That Shape Our Weather and Climate cover in CCEA A-Level Geography?

8 subtopics: the global energy balance, vertical and horizontal heat transfer in the atmosphere, ocean currents and the transfer of heat, pressure belts, the coriolis effect and the pressure gradient, the tri-cellular model, the global winds, and where it breaks down, jet streams and the upper westerly winds, global patterns of temperature, pressure, wind and precipitation and factors influencing air temperature. Each one has its own page with questions and model answers.

How is The Processes That Shape Our Weather and Climate organised?

By the CCEA 3910 specification, subtopic by subtopic, so it matches the order you are taught it in.