atmospheric redistribution

• • due to earths curve sun rays are concentrated over a smaller surface area at tropical latitudes resulting in more energy
• • rays have less energy to pass through at the tropics so less energy is lost to absorption and reflection
• • albedo differs between the poles and tropics
  • dark forest surfaces absorb radiation whereas light surfaces at the poles have a higher albedo so reflect more
• • due to earths tilt the poles receive no insolation during winter solstices whereas the tropics receive insolation all year
• in the northern hemisphere -

  • coriolis effect deflects winds to the right due to earths spin
  • warm air is distributed to cool altitudes and cold air distributed to warmer altitudes
• • hadley and polar cells are thermally direct and ferrel cell is thermally indirect
• hadley cell -

  • warm air rises at equator creating low pressure
  • air splits in atmosphere and moves polewards
  • cool are sinks at 30$^{\circ}$ creating high pressure
  • north east trade winds move air back to equator completing the hadley cell
• polar cell -

  • cold air sinks at poles creating high pressure
  • polar easterlies transfer cold air from poles towards the equator
  • meets air from tropics causing it to rise
  • air moves back to poles in upper atmosphere completing the polar cell
• ferrel cell -

  • located between 30$^{\circ}$N and 60$^{\circ}$N
  • transfers air between hadley and polar cell
  • forms the westerlies