Global Atmospheric Circulation

• What is global atmospheric circulation?

  Transfer of heat from the equator to the poles by the movement of air (how air moves heat around the world)
• Why do air move in the first place? (Global Atmospheric Circulation)

  Difference in air pressure- wind blows from high pressure to low pressure
• What influences the weather? (Global atmospheric circulation)

  Pressure belts and surface wind patterns
• What happens at the high pressure belt?

  Cool air descends
• What happens at the low pressure belt?

  Warm air ascends
• What is global atmospheric circulation?

  A system of winds that transports heat from the equator to the poles, driven by the sun’s energy and the Earth’s rotation.

  
• Why is it hotter at the equator than at the poles?

  The sun’s rays are more concentrated at the equator, hitting it directly, while they are more spread out at the poles due to the Earth’s curvature
• What causes air to move in the atmosphere?

  Differences in temperature and pressure between the equator and the poles cause air to rise and fall, creating wind
• Name the three cells in global atmospheric circulation

  Hadley cell, Ferrel cell, and Polar cell
• What happens in the Hadley cell?

  • Warm air rises at the equator, causing low pressure and heavy rainfall (tropical rainforests)
  • It then cools and sinks around 30° north and south, creating high pressure and dry conditions (deserts)
• What happens in the Ferrel cell?

  Air moves from the sub-tropical high pressure to sub-polar low pressure, creating changeable weather typical of the UK (mild, wet)
• What happens in the Polar cell?

  Cold air sinks at the poles (high pressure), then flows toward 60° where it rises, causing low pressure and snowy conditions
• What type of weather is caused by low pressure?

  Rising air leads to condensation, cloud formation, and rain – common at the equator and 60° N/S
• What type of weather is caused by high pressure?

  Sinking air means dry, clear skies – found at 30° N/S (deserts) and the poles
• Why is the UK’s weather mild and wet?

  The UK lies at about 55°N, on the boundary between the Ferrel and Polar cells, where low pressure brings rain and unsettled weather
• Why are tropical rainforests found near the equator?

  Rising air at the equator causes low pressure and heavy rainfall, perfect for rainforest growth
• Why are hot deserts found around 30° north and south?

  Sinking air from the Hadley cell creates high pressure and dry, hot conditions