Weather hazards Flashcards
What is atmospheric circulation?
The general movements of air around the Earth due to pressure and temperature
What are the characteristics of the Hadley cell?
Hot air rises at the equator, creating a low pressure belt. The intensity of the sun’s rays lead to rapid rising or air and huge cumulonimbus clouds
Surface winds move towards the equator whilst high winds move away from the equator and descend around 30°N
What is the Hadley’s cell’s influence on climate?
Surface winds bring moisture to the equator. This rises and then it rains (convectional rain-fall)
What are the characteristics of the Ferrell Cell?
Air sinks at 30°N, creating high pressure. Surface winds move outwards towards the poles
What is the Ferrell cell’s influence on climate?
Air descends at 30°N. It warms=dry, arid conditions
As air rises at 60°N. It creates rain clouds
What are the characteristics of polar cells?
Air sinks at the poles creating a high pressure belt. Surface winds move away from the poles which gradually warm and rise at 60°N
What is the Polar cell’s influence on climate?
Air descends at the poles meaning, cold, dry conditions. Cold air has limited ability to hold water vapour
What are some of factors needed for tropical storms?
Temperature
Wind shear
Rotation
Air pressure
Why is temperature important for a tropical storm?
Ocean temperatures must be around 26°C-27°C and at least 50 metres deep. Warm water provides the storm with energy. this is why storms form during late summer, when the ocean has had time to heat up
Why is air pressure important for a tropical storm?
Tropical storms must be in areas of unstable air pressure. This is usually where areas of high pressure and low pressure meet-so that warm air rises more readily and clouds can form (this air must also be humid for cloud formation) Warm air rises because it is less dense than cold air
Why is wind shear important for a tropical storm?
Winds must be present for the swirling motion to form, but not too strong or the storm system will be ripped apart in the early stages
Why is rotation important for a tropical storm?
Tropical storms only form around the equator (5°-15°) but tropical storms will not form on the equator.
The Coriolis effect is the effect of the Earth’s rotation on weather events. The storm spins because the Earth is spinning; but there is no Coriolis Effect at the equator, hence why these storms will only form a certain distance away from it
Describe the formation of tropical storms?
-Sun sends incoming solar radiation to Earth which warms our oceans to 27°C
This causes warm air to rise. This gives low pressure at the centre of the storm
This air cools as it rises causing condensation to occur, clouds to form and rain to occur
Some cooled air sinks back down helping to create the eye
Air rushes in from higher pressure areas outside of the storm to lower pressure areas at the centre of the storm creating winds
The whole storm rotates because of the Earth’s spin (Coriolis effect)
When did Typhoon Haiyan hit the Philippines and how strong was it?
7th November 2013
Category 5 super typhoon
How many people died in Typhoon Haiyan?
6,300 (many claim this figure to be higher)
How many people were displaced as a result of Typhoon Haiyan?
Over 600,000
How many homes were damaged or destroyed in Typhoon Haiyan?
40,000
As well as the storm surge, what were the other primary effects of Typhoon Haiyan?
Heavy winds destroyed buildings, power lines, crops and other infrastructure
Heavy rain (over 400mm) causing flooding
How many people lost their source of income due to Typhoon Haiyan?
6 million
How did Typhoon Haiyan affect health?
There were major shortages of water and shelter
The outbreak of disease was feared due to poor sanitation conditions in shelters and overwhelming amounts of dead bodies
What other secondary effects did flooding have after Typhoon Haiyan?
Triggered landslides, which blocked roads and slowed relief efforts
How did international aid organisation respond to Typhoon Haiyan?
They brought food, water, aid supplies and temporary shelters to support those affected
How many evacuation centres were set up to help the homeless during Typhoon Haiyan?
1,200
How did the UNDP support locals whilst also funding the clean-up process after Typhoon Haiyan?
They set up cash-for-work schemes which paid villagers to clear debris and medical waste
How have fishing and agricultural sectors recovered from Typhoon Haiyan in the long term?
Fishing boats donated by organisations like Oxfam supported the fishing sector.
Rice farming and fishing was quickly re-established
What was another long term strategy put in place after Typhoon Haiyan to reduce risk?
More cyclone shelters are being built.
Homes are being built away from vulnerable areas
What are the Somerset levels?
An area of low-lying coastal plains and wetlands in the south-west UK, located in the county of Somerset
What were the 3 main causes of the Somerset Levels floods?
Heavy and Prolonged rain
High tides and storm surges caused higher river levels
Lack of dredging reduced river capacity
How many homes were flooded and how many farms had to be evacuated during the Somerset levels floods?
Over 600 homes and 16 farms
What was the estimated cost of damage from the Somerset levels floods?
£10 million
How was agricultural land affected during the Somerset levels floods?
A lot of agricultural land was flooded-over 14,000 ha of agricultural land was underwater for 3-4 weeks
Why were some people left stranded during the Somerset levels floods?
Some villages, such as Moorland, were completely cut off by flood water
How did the Somerset levels floods affect the environment?
Floodwater transported sewage, chemicals and debris to other areas and affected the Levels ecosystems
How was stagnant water dealt with after the Somerset levels floods?
Water had to be reoxygenated before being pumped back into the river
What is the 20-year plan that aims to manage and reduce risk in Somerset called?
The Somerset Levels and Moors Flood Action Plan
How much money did the UK government promise to give to help with repairs after the Somerset levels floods?
At least £30 million
What were some of the immediate responses during the Somerset levels floods
Rescue boats were deployed to help stranded people
Extra police patrols in response to more reports of crime
Suggest why the UK’s weather might be becoming more extreme?
There have been several extreme weather events since 2000
Heatwave in 2003, heavy snowfall in 2009 and 2010 and Somerset Level Floods in 2014. These have all broken weather records which highlight the extreme nature of these events for the UK
May be linked to climate change (mor e intense weather events)
The atmospheric circulation models may be affected by warming temperatures (floods to dry areas and heatwaves in cool areas)
