Weather Hazards Flashcards
high pressure
- sinking air
- calm clear or sunny
- sometimes trapped cloud or fog
- DRY
low pressure
- rising air
- as air rises and cools clouds and rain form
- BAD WEATHER
- storms are areas of low pressure that bring strong winds and heavy rain
what is the coriolis effect
tropical storms ROTATE anti-clockwise in the northern hemisphere and clockwise in southern
what is the ITCZ?
2 warm air masses that meet at the equator
what are jet streams
strong, high altitude currents of air
HADLEY CELL
equator, low pressure
FERRELL CELL
- 30° N/S, high pressure
POLAR CELL
- 60° N/S, low pressure
what factors are necessary for a tropical storm to form?
- sea temp ABOVE 27°C to a depth of 60 metres
- earth rotating generates spin = coriolis effect
- light winds, carries storm but doesn’t break up clouds
- thunderstorms clustered
- only occur late summer/early autumn
- LOW air pressure
- between 8-20° latitude (tropical)
- over large body of water
how do tropical storms form?
- need lots of heat, form over seas
- sun is close to equator, providing energy to heat ocean
- warm ocean heats air above it causing it to rise rapidly
- water evaporates quickly from hot surface of ocean = rising air contains lots of water vapour
- rising air starts to spin (coriolis effect) = eye of storm is calm
- as the air rises it cools, condenses + forms clouds
- rapidly rising air creates areas of low pressure
- low pressure sucks in air, causing strong winds
- once the storm moves over land it loses energy and fades
where are the strongest winds!
eye wall
how will climate change affect tropical storms
- temp increased = sea is warmer
- tropical storms will happen more as sea is warmer for longer
- happens in more new places as sea will be warmer
- stronger as sea levels rise so flood small/low lying islands. storms can be powerful for longer
what were the PRIMARY IMPACTS of Typhoon Haiyan?
- 5metre high storm surge with 314km/h winds
- killed 6190
- power interrupted, 4.1 mill homeless, 1.1 homes damaged
- rice + seed sticks damaged. cost $53 mil. 1.1 mil crops damaged
- 75% of fishermen + farmers lost income
- airport destroyed (no aid or evacuation)
- 90% of tacloban destroyed
what were the SECONDARY IMPACTS of Typhoon Haiyan?
- oil barge ran aground = 800,000l oil spill
- contaminated 10 hectares of mangroves
- looting - survivors fought for food and supplies
- price of rice increases by 11%
- 8 deaths in rice stampedes
- diseases and infections spread
- homelessness + begging = more deaths
what was the RESPONSE of Typhoon Haiyan?
- president televised a warning
- 800000 evacuated before storm
- supplies arrived soon after airport reopened
- large companies donated $1.5 bil
- Build Back Better
- no build zone along coast
- storm surge warning system
- mangroves
what were the CAUSES of Typhoon Haiyan?
- sea temp above 27°C
- low air pressure
- late summer / autumn
- 5°-20° tropical location
- sufficient coriolis
why were the IMPACTS of Typhoon Haiyan so bad?
an NEE- not as much money as USA/UK. many live in poverty
DROUGHT
no/not enough water.
- eg. southern and eastern england 2012
-
FLOOD
river bursting banks due to lots of rain
- eg. Devon and Cornwall cut off by road and rail in april 2012
STORM
in 2005 a tornado caused 19 injuries + £40 mill damage in birmingham
HEAT
in 1975 temp exceeded 32°C for a week in Cheltenham
Cold
first day of british summer time 2013 temps of -11°C in Braemar
what were the PRIMARY IMPACTS of Somerset Levels Floods?
SOCIAL:
- 600 houses flooded
- 16 farms evacuated
- residents evacuated to temporary homes for months
- villages cut off (affected daily lives)
- power supplies cut off
ECONOMIC:
- total flood cost £10 million
- over 14000 ha of land under water for 4 months
- over 1000 livestock evacuated
- local roads cut off affecting business
- railway closed
what were the SECONDARY IMPACTS of Somerset Levels Floods?
ENVIRONMENTAL:
- flood water heavily contaminated
- stagnant water had to be re oxygenated before pumped back into rivers
- much of soil severely damaged = infertile
- may take up to 2 hrs to restore soil for crops
what were the CAUSES of Somerset Levels Floods?
- 100mm more rainfall than usual in Jan and Feb
- storm drains couldn’t cope
- rivers not been dredged in 20years = build up of silt
- wide and flat = nowhere to drain water
- heavy rainfall on already saturated soil from Nov and Dec
how are the impacts being reduced in long term (Somerset Level floods)
- earth embankment in thorny (£180000]
- £20 mill flood plan:
- rivers dredged
- road levels increased
- community flood defences
- river banks raised and strengthened
- more pumping stations
- in 2024 tidal barrage
what was the IMMEDIATE RESPONSE of Somerset Levels Floods?
- FLAG action group
- villagers evacuated
- royal marines to build sand bag walls
- flood warning given in advance
- RSPCA rescued cattle and animals
what evidence is there for climate change?
- TREE RINGS - trees sensitive to change in temp, sunlight and rain. 10000+ yrs. warm years = wide rings + vice versa
- ICE CORES - 800000 yrs. drill down in antarctica. in ice air bubble trapped and O2 isotopes can be analysed to accurately work out what climate used to be like
- SEA LEVELS CHANGE - 100yrs. warm oceans = thermal expansion = sea levels increase. glaciers and sea ice melt = sea levels increase
what are the natural causes of climate change?
ORBITAL CHANGES - earth’s orbit around sun is constantly fluctuating eclipse. ranges on a 100000 yr cycle. when earth is closer to the sun climate gets warmer. tilt angle exaggerates the climate
VOLCANIC ACTIVITY- short term = colder (sun blocked by ash clouds). long term = warmer (lots of g gas emitted)
SUN SPOTS - more sun spots = increased suns magnetic activity =sun radiates more heat = increased temperature
what are the human causes of climate change?
- BURNING FOSSIL FUELS. 50% of all carbon emissions.as pop increases demand for energy increases which increases amount of fossil fuels burnt and CO2 releases
- DEFORESTATION. often trees are burnt releasing more CO2. 20% of all emissions. trees absorb CO2 but stop when cut down
- AGRICULTURE. trees cleared for cattle and crops. methane from cows and rice paddy fields (methane 64x worse than CO2)
SEA LEVELS RISIMG
increased flooding, people forced out of homes. animals lose habitats
flood risks
low lying land has increased flood risk eg, somerset levels
glaciers melting
increased sea levels increase flooding
water shortages
hosepipe bans in HICS, people without clean water in LICS
impact on wildlife
deforestation = habitat and biodiversity loss. temp becomes too hot for animals in some places (coral bleaching)
spread of disease
new mosquitoes and diseases released from melting ice
affect on food production
droughts= soil too dry
flood = infertile soil
cannot grow crops
MITIGATION STRATEGIES
- ALTERNATE ENERGY PRODUCTION
- renewable energy doesn’t release g gases and enhance greenhouse effect
- can be unreliable and expensive to put in place - carbon capture and storage
- use tech to capture CO2 from fossil fuel combustion and inject it into underground reservoirs
- decrease amount of CO2 released into atmosphere
- incredibly costly and what if carbon accidentally released - PLANTING TREES
- absorb CO2. if planted regularly they can become a carbon sink and take in more CO2 than released when cut down - INTERNATIONAL AGREEMENTS
- agreements to reduce emissions by a date
- encourages people and businesses to use greener energy to reach targets
- not all governments initially agree and no real penalties if failed
ADAPTATION STRATEGIES
- CHANGE JN AGRICULTURAL SYSTEMS
- altering what they grow depending on changing climate
- eg, drought resistant crops
- farmers still make a living but people may need to change diets - MANAGING WATER SUPPLY
- londoners consume most water and is driest part of UK
- Increasing supply: water from river thames and reverse osmosis = drinking water. transport water from wetter regions/ reservoirs - REDUCING RISK FROM RISING SEA LEVELS
- eg. thames barrier against tidal surges in London
- LICs can plant mangroves to provide a barrier. less effective but affordable.
