weather - natural hazards

• Global atmospheric circulation model


  a model representing how air moves around the globe, and helps determine patterns of weather and climate.
• Explain how latitude impacts on average global temperatures


  Temperatures are typically warmer at the equator and cooler at the poles. As latitudes increase, the average temperature is cooler. This is because the sun's rays are less direct and gets less radiation due to the curve of the earth.
• ITCZ

  Intertropical convergent zone is a low pressure belt that moves north and south of the equator where the trade winds meet. Typically bringing heavy rain.
• Tropopause 


  stops air from escaping into space.
• Troposphere


  the area between lowest layer of the earth's atmosphere to the crust.
• As cool air sinks it creates high pressured zones and less rain.
• As warm air rises it creates low pressured zones and more rain.
• 3 cells in the global atmospheric circulation model

  • hadley cell
  • ferrel cell
  • polar cell
• short wave radiation = light (cannot feel)

  long wave radiation = heat (can feel)
• Winds do not move perfectly north or south due to the coriolis effect , which causes the wind to deflect and bend to the earth's rotation. The coriolis effect also creates depressions and tropical storms.
• Jet stream


  Are strong high altitude winds about 5-7miles above the earth's surface and moves from west to east.
• During WW2 USA military aircrafts travelled against a jet stream towards Japan, causing their bombs to miss their target on the country
• Polar front jet stream is found between the ferrel and polar cell.
• Conditions for a tropical storm to form

  • form at warm seas 26celsius and 50m deep
  • found at low pressure zones (ITCZ)
  • found 10-20 degrees north or south of the equator
  • found at where the trade winds converge
  • needs a lot of heat energy and moisture
  • the coriolis effect causes the spinning force to form hurricanes
• Formation of a tropical storm

  1. tropical disturbance
  2. tropical depression
  3. tropical storm
  4. category 1 hurricane
  5. decay
• Tropical disturbance (1)


  warm air passes warm tropical oceans of 10-20degrees from the equator. The heated air rises, as the water vapour cools it forms a cluster of cumulo-nimbus clouds.
• Tropical depression (2)

  After a few days, the pressure at the centre of the storm is very low, the coriolis effect causes it revolve with low wind shear to prevent it from breaking. The revolving system is blown west by easterly blowing trade winds.
• Tropical storm (3)


  The entire tropical depression has expanded in size and gale strong winds of 40mph. Lots of warm rising water vapour which releases latent heat increases the energy levels for the storm .
• Category 1 hurricane (4)


  it rotates at faster speeds anticlockwise and wind speeds exceed 75mph.
• Decay (5)

  the hurricane dies when reaching land due to friction and sources of heat energy and moisture are lost.
• Eye wall


  intense torrential rainfall and winds are the strongest here.
• Eye


  around 50km, no rain and an area of calm.
• Rainbands 


  away from the eye, the outer spirally bands of thunderstorm clouds bear heavy rain and strong winds.
• Storm surge


  A natural hazard where there is a large rise is sea levels due to a tropical storm.
• Saffir Simpson scale


  A scale which helps determine the intensity of the storm

  • Category 1 = 74-95mph = minimal damage
  • Category 2 = 96-110mph = moderate damage
  • Category 3 = 111-129mph = extensive damage
  • Category 4 = 130-156mph = extreme damage
  • Category 5 = 157+mph = catastrophic damage
• Preparation (reducing affects of a hurricane)

  • houses close to sea are constructed on stilts
  • information films shown on television alert and educate residents
  • the effects of hurricanes are taught in schools
  • all cities need to have emergency procedures so residents and emergency services know how to react
  • national "Hurricane Preparedness Week" ran every year in towns and cities (this happens in Japan)
• Protection (reducing affects of a hurricane)

  • Sea walls are built to protect important buildings along coastal areas
  • Shutters are attached to windows to keep it from shattering
  • Houses close to sea are constructed on stilts
• Prediction (reducing affects of a hurricane)

  • weather satellites monitor the track of hurricanes and alert residents to evacuate in an emergency.
• extreme weather events top-down strategies - drought

  • MET office warnings
  • increase water shortage capacity
  • water companies help
  • impose hose pipe ban
• extreme weather events top-down strategies - flooding in London

  • MET office warnings
  • building flood defences and better drainage systems
  • Thames barrier which protects coastal flooding
• extreme weather events top-down strategies - cold weather

  • MET office warnings
  • grit icy roads
  • removing snow from the roads (snow plough)