Weather hazards Flashcards
What is the global atmospheric circulation?
The movement of air across the globe in specific patterns.
How does the global atmospheric circulation influence our biomes?
It creates winds across the planet and leads to areas of high rainfall e.g. tropical rainforests, and areas of dry air e.g. deserts.
What happens in the Hadley Cell?
Ground at equator intensely heated by sun. Causes air to rise = low pressure zone. Air rises, condenses and forms thick storm clouds. Air continues to rise to upper atmosphere.
Where does the Ferrel Cell occur?
Between 30° and 60° north of the equator, and between 30° and 60° south of the equator.
What happens in the Ferrel Cell?
Air on the surface is pulled towards the poles, forming winds. Winds pick up moisture as they travel over oceans. At 60°N&S, winds meet cold air from poles. Where the two air masses meet, there are unstable weather conditions e.g. wet, windy weather in UK.
What happens in the Polar Cell?
At the poles, air is cooled and sinks towards the ground = high pressure. Then flows towards lower latitudes (60°N&S). Cold polar air mixes with warmer tropical air and rises upwards = low pressure and unstable weather.
Why is weather hot and wet at the equator?
Hadley Cell causes air to rise at the equator = low pressure = lots of cloud formation = rainfall. Sun’s rays have to travel through less atmosphere to reach equator (than poles) so heat is more intense.
Why is weather cloudy and wet in the UK?
Located at 55-60°N, at boundary of Ferrel Cell and Polar Cell. Warm air mass meets cold air mass = low pressure & unstable weather conditions.
Why is weather hot and dry in the desert?
Deserts found approximately 30°N&S. Air here is sinking (at top of Hadley Cell) = high pressure = very little air rising = very little condensation = very little rainfall.
What is a tropical storm?
A natural hazard that brings heavy rainfall, strong winds and other related hazards e.g. mudslides and floods.
What are the different names given to tropical storms?
Hurricanes, typhoons and cyclones.
What are the conditions required for tropical storm formation?
Warm oceans – 27°C or above. Spin created by the Coriolis Effect. Unstable, rapidly rising air. Little wind shear (light winds blowing high up in the atmosphere).
How are tropical storms structured?
Eye of storm – centre of storm; high pressure = no clouds; calm conditions. Eye wall – either side of eye; low pressure = unstable conditions and rising air = severe wind, rain, thunder, lightning. Either side of eye wall – smaller thunderstorms, strong winds and heavy rain.
How are tropical storms formed?
Water vapour evaporates from warm ocean surface. Evaporated air rises, cools, condenses = forms towering thunderstorm clouds. As air condenses, heat is released, powering storm and drawing more warm ocean water, creating more thunderstorms. Thunderstorms join together to form giant spinning storm. Officially a tropical storm when winds 75mph. Storm develops eye at centre. Air descends rapidly here = high. Tropical storm carried across ocean by prevailing winds, gathering strength from ocean. pressure = calm conditions.
Why do tropical storms weaken when they reach land?
Energy supply (warm ocean water) is cut off and because there is friction with the land.
How is hurricane strength measured?
Using the Saffir-Simpson Scale.
How will climate change affect tropical storm distribution?
Distribution will increase as more oceans will become warm enough for tropical storm formation.
How will climate change affect tropical storm frequency?
Frequency is expected to decrease in the future.
How will climate change affect tropical storm intensity?
Intensity is expected to increase.
How certain are we about how climate change will affect tropical storms?
Pretty certain, but our predictions are based on models. We do not yet have enough data to make accurate predictions.
When and where did Typhoon Haiyan occur?
In November 2013, in the Philippines.
How strong was Typhoon Haiyan?
Category 5 on the Saffir-Simpson Scale.
What were the primary effects of Typhoon Haiyan?
6,300 people were killed - most drowned. Power supplies were cut off for a month in some areas and a terminal at Tacloban Airport was badly damaged. 30,000 fishing boats were destroyed
What were the secondary effects of Typhoon Haiyan?
6 million people lost source of income. Flooding caused landslides & blocked roads. Water, shelter & food shortages led to disease. Looting & violence in Tacloban.
What were the immediate responses to Typhoon Haiyan?
1,200 evacuation centres set up to help homeless. UK government sent shelter kits. Philippines Red Cross delivered food aid i.e. rice, canned food, sugar, salt & cooking oil.
What were the long-term responses to Typhoon Haiyan?
Roads, bridges & airports rebuilt. ‘Cash for Work’ programme paid people to clear up and rebuild Tacloban city. Oxfam helped to replace fishing boats.
How can we reduce the effects of tropical storms?
Monitoring, prediction, protection and planning.
What do monitoring and prediction of tropical storms involve?
Using technology to predict the course (track) the storm will take. National Hurricane Center, Miami predicts course of storms & issues warnings.
How can we use protection to reduce the effects of tropical storms?
Reinforcing windows & doors against winds.Building sea walls to protect property from storm surges. Building houses on stilts.
How can we use planning to reduce the effects of tropical storms?
Raise individual and community awareness about dangers & how to respond to them. Encourage people to devise emergency action plans.
What weather hazards does the UK experience?
Thunderstorms, prolonged rainfall, drought, heatwaves, heavy snow.
Why does the UK experience extreme weather?
The UK is affected by: Arctic air which can bring snow & cold weather; Winds from the east, bringing wintry weather; Winds from south, bringing hot & sunny weather; Storms from the Atlantic – heavy rain & strong wind.
What were the impacts of the Beast from the East?
4 dead, Temperatures down to -12°C in some places, Thousands of schools closed, Flights cancelled at Heathrow Airport.
Where are the Somerset Levels?
In south-west England. Located between the Mendip Hills, Quantock Hills & Bristol Channel.
Describe the Somerset Levels.
An extensive area of low-lying farmland and wetland.
Why do the Somerset Levels experience flooding?
The area is drained by many rivers, such as the River Tone and River Parrett.
What caused the 2014 Somerset Levels floods?
Jan 2014 was wettest Jan since records began. 350mm of rain fell in Jan; 100mm above average. Rivers were clogged with sediment; had not been dredged for 20+ years.
What were the impacts of the 2014 Somerset Levels floods?
Social – 600 houses flooded, 16 farms evacuated. Economic – Cost £10 million+, 1,000 livestock evacuated. Environmental – Floodwater contaminated with sewage & pollutants, oxygen levels in stagnant water dropped.
What were the immediate responses to the 2014 Somerset Levels floods?
Immediate – villagers used boats to get to work & school. Volunteers supported those affected.
What were the long term responses to the 2014 Somerset Levels floods?
Long-term – £20 million flood action plan, Rivers Tone & Parret dredged in 2018, river banks raised.
Is there evidence for extreme weather increasing in the UK?
Yes. Lots of storms, snow, heatwaves, droughts, torrential rain in the past couple of decades.
