tropical storms

• What creates areas of high pressure?

  sinking air
• What weather does sinking air + high pressure lead to?

  dry weather
• What creates areas of low pressure?

  rising air
• What weather does rising air + low pressure lead to?

  Wet weather, because as air rises, it cools and condenses forming clouds
• Where is it hottest on earth and why?

  The equator is hottest as the Sun’s energy (solar insolation) is more concentrated
• Where are the low pressure belts?

  The equator and 60° north and south
• Where are there high pressure belts?

  The 30° and 90° (the poles) north and south
• What are the cells in the global atmospheric circulation model? 

  Hadley - the movement of air between the equator and 30°.  Rising at the equator, sinking at 30°

  Ferrel - the movement of air between the 30° and 60°.  Sinking at 30°, rising at 60°

  Polar - the movement of air between the 60° and the poles.  Rising at 60°, sinking at the poles
• What determines the wind direction?

  Winds blow from areas of high pressure to areas of low pressure
• What are trade winds?

  Winds that blow from 30° north and south to the equator
• What are westerlies?


  Winds that blow from the west to the east from 30° north and south to 60°
• What are easterlies?


  Winds that blow from the east to the west from the poles to 60°
• What is the global atmospheric circulation model?

  The worldwide system of winds, which transports heat from tropical to polar latitude
• Where do tropical storms form ?

  Between 5 and 15° north and south of the equator
• What are names for tropical storms?

  Hurricanes, cyclones and typhoons
• How are tropical storms measured?

  Measured on the Saffir-Simpson scale from 1-5.
• What conditions do tropical storms need?

  Warm water over 27° so that air can rise

  Coriolis effect

  Low winds in the upper atmosphere (wind shear)
• What is coriolis effect?

  The centre of the earth is spinning faster than the high latitudes, creating a spin effect on storms as air is deflected
• How do tropical storms form?

  1. Warm water evaporates at the ocean surface
  2. Warm moist air cools and condenses as it rises to form towering clouds
  3. The coriolis effect and trade winds cause the air to spin
  4. More evaporation takes place.  Air condensates releasing latent heat into the storm system
  5. Air is also drawn in from high pressure areas, adding wind  to the system
  6. As winds reach 120kmph a tropical storm is formed
  7. Prevailing (the strongest) winds blow the storm across the ocean
  8. It loses energy when it is no longer over warm water and so dies out
• What is the structure of a tropical storm?

  A calm and clear eye at the centre.

  High banks of cloud either side of the eye - called the eye wall.

  Smaller cloud  banks further out spin in a spiral
• What are the conditions in the eye wall?

  Wind speeds of over 120 km/h

  Torrential rain, thunder and lightning

  Low pressure.  Tall banks of cloud
• What are the conditions in the eye?

  Calmer weather - high temperatures and clear skies.  Cold air sinks, creating an area of high pressure
• How will climate change affect tropical storm distribution?

  How will climate change affect tropical storm distribution?

  Distribution means where they are found

  Warming ocean temperature means that more areas are likely to experience tropical storms.

  The distribution will widen

  For example Brazil, 2004
• How will climate change affect tropical storm frequency?


  Frequency is how often

  It is unclear whether this will affect the frequency of tropical storms
• How will climate change affect tropical storm intensity?

  Intensity is how strong

  Hurricane intensity in the North Atlantic has risen in the last 20 years. This appears to be linked to increases in sea surface temperatures.
• What is a storm surge?

  A change in sea level

  The wind pushes the sea level higher, and low pressure pulls the sea level up
• What is the key information about Typhoon Haiyan?

  • In the Philippines 
  • NEE (Newly Emerging Economy)
  • Category 5 - wind speeds of 275 kph
  • 5m high storm surge
• What were the primary effects of Typhoon Haiyan?

  • 6300 killed
  • 90% of Tacloban city destroyed
  • 1 million homes destroyed
  • 71000 hectares of rice farmland destroyed 
  • $5.8 billion of damage
• What were the secondary effects of Typhoon Haiyan?

  • Damaged water supplies led to diseases like diarrhoea
  • 6 million people lost their sources of income in fishing and farming 
  • Widespread looting
• What are the immediate responses to typhoon Haiyan?

  • Government evacuated 800,000 people
  • Red Cross supplied 1.1 million people with water
  • The UK sent shelter kits, which included lights, blankets, cooking equipment, water filter
• What are the long-term responses to typhoon Haiyan?

  • Build Back Better programme built typhoon resistant housing
  • $88 million was donated internationally to help with clean-up
  • Oxfam helped to repair fishing boats
  • UN Cash for Work programme paid villagers to help clean up
• How can monitoring and prediction reduce the effects of tropical storms?

  Satellites monitor cloud formation 

  Aeroplanes monitor temperature, humidity, rainfall and wind speed

  These are used to predict where tropical storms are going to land by predicting their course (track)
• How can protection reduce the effects of tropical storms?

  Building specifically designed storm shelters with:

  • Strong concrete
  • Raised ground and stilts
  • Shutters over window

  Sea walls can also be built to protect against storm surges
• How can planning reduce the effects of tropical storms?

  • Teach disaster preparation in schools
  • Run regular hurricane drills
  • Train emergency services
  • Ensure citizens have emergency supply kits
  • Systems to issue warnings - by bicycle, television, radio, social media
• What is extreme weather?

  When a weather event is significantly different from the average or usual weather pattern
• What extreme weather affects the UK?

  1. Thunderstorms after hot weather in the summer -> flash flooding in localised areas.
  2. Storms from the Atlantic bring prolonged rainfall over a long period -> flooding over a wide area especially in winter.
  3. Strong winds from Atlantic storms -> damage buildings, cause death and cut electricity supplies.
  4. Arctic air can bring heavy snow to and very cold conditions.
  5. Hot and sunny weather from the South -> heatwaves and droughts - many elderly people die and less food supply
• Is the UK’s weather becoming more extreme?

  Yes - Climate change is increasing the amount of extreme weather experienced by the UK.
• What evidence is there that the UK’s weather is becoming more extreme?

  • All of the UK's top 10 warmest years, in the time series from 1884, have occurred this century.  More extreme heat
  • Six of the 10 wettest years on record have occurred since 1998. Records began in 1862.  Got wetter

  The average coldest day of the year has become 1.7 °C milder at -6.8°C, compared to -8.5°C between 1961-1990. Less extreme cold
• What is the key information about the Somerset Levels?

  • Extreme Flooding
  • December 2013- February 2014
  • Somerset is in South-West England
• What were the causes of the Somerset Levels floods?

  Physical

  Heavy rainfall - Jan 2014 was the wettest on record. 350mm of rainfall in Jan and Feb

  High tides meant the water could not escape out into the sea

  Human

  Rivers had not been dredged for 20 years, so had reduced capacity

  Urbanisation made it harder for water to drain