Weather Hazards Flashcards
Polar insolation
Over large surface area of Earth, ‘Albedo effect’
Albedo effect
Sun’s rays are reflected off white snow/ice in poles
Equatorial Insolation
Over small surface area of Earth
Equator
0º on lines of latitude
Tropic of Cancer
23.5ºN on lines of latitude
Tropic of Capricorn
23.5ºS on lines of latitude
Artic Circle
66.5ºN on lines of latitude
Antarctic Circle
66.5ºS on lines of latitude
Wind
Air that moves from high to low pressure, Coriolis effect, Northern hemisphere forces winds to curve to right, so winds will blow clockwise, Southern hemisphere forces winds to curve to left, so winds will blow anticlockwise
Coriolis effect
Winds don’t blow in straight line as Earth is rotating
Weather in UK
Cloudy + wet as UK is in boundary of Ferrel + Polar cells + as there is low pressure from rising air
Low pressure
Where hot air rises, so weather is cloudy + rainy
High pressure
Where cold air sinks, so sky is clear + there is dry + clam weather
Weather in desert
Hot + dry due to high pressure, so there is lack of rainfall + clouds, lack of clouds makes it very hot during day, but very cold at night as heat is lost from ground, lack of rainfall makes it desert
Equator weather
Hot + humid due to low pressure, making weather very wet + cloudy, air rises due to equatorial insolation heats up air, making it rise + very hot
Hadley cell
It’s largest cell
Ferrel cell
Travels in opposite way to polar or hadley cells
Tropical storm
Huge storm that forms + develops in Tropics, USA + Caribbean - hurricanes, Japan + Philippines - typhoons, Australia + South-east Asia - cyclones, form above 27ºC
Extreme weather
When weather event is significantly different from average/usual weather pattern + it’s especially severe or unseasonal
Global Atmospheric Circulation
Movement of air + heat across Earth, creates areas of high rainfall e.g tropical rainforests + areas of dryness e.g deserts,
Distribution of Tropical Storms
Form 5-15º North or South of Equator (in Tropics) as they need water to be 27ºC or hotter to form, majority form in Northern Hemisphere
Formation of a Tropical Storm
Strong upward movement of air draws water vapour up from warm ocean surface, this evaporated air cools as it rises + condenses to form towering thunderstorm clouds, as air condenses, it releases heat which powers storm + draws up more + more water from ocean, several smaller thunderstorms join together to from giant spinning storm, now develops eye +, therefore, eye wall too, as storm is carried across ocean by prevailing winds, it continues to gather strength, on reaching land, storm’s energy supply is cut off, friction with land slows it down + it begins to weaken, if storm reaches warms seas after crossing land, it may pick up strength again
Eye
Centre of storm, where air descends rapidly
Eyewall
Outer edge of eye, where most intense weather conditions are felt
Typhoon Haiyan: Primary Effects
6,300 people were killed, 30,000 fishing boats destroyed, 90% of Tacloban City is destroyed
Typhoon Haiyan: Secondary Effects
Flooding caused landslides + blocked roads, 6 million people lost their source of income, looting + violence broke out in Tacloban City
Typhoon Haiyan: Immediate Responses
800,000 people were evacuated by authorities, 1,200 evacuation centres set up, $1.5 billion pledged in aid from other countries
Typhoon Haiyan: Long-term Responses
Rice farming + fishing was quickly reestablished, Roads, bridges + airport facilities rebuilt, More cyclone shelters built
Effect of climate change on tropical storms
Frequency will decrease, intensity will increase due to rising sea temperatures, distribution will change + they may affect areas outside current hazard zone
Tropical Storms: Monitoring and Prediction
Technological developments have made monitoring + prediction more accurate + effective, In North Atlantic, there are two levels of warning issued by National Hurricane Centre, hurricane watch - advises that hurricane conditions are possible, hurricane warning - advises that hurricane conditions are expected + that people should take immediate action
Tropical Storms: Protection
Buildings: built on stilts + raised land, shutters over windows, constructed of strong concrete
Tropical Storms: Planning
Raising individual + community awareness, In USA there is National Hurricane Preparedness Week - focuses on educating people about potential dangers ahead of next hurricane season + families are encouraged to devise their own plan of action
Causes of extreme weather in the UK
Storms from Atlantic bring heavy rain + strong winds, hot + sunny weather from south can lead to heatwaves + droughts, severe weather can come from east e.g Beast from the East, Artic air can bring heavy snow + bitterly cold conditions
Somerset Levels Floods: Causes
Rivers hadn’t been dredged for 20 years + had become clogged with sediment, high tides + storm surges swept water up rivers from Bristol Channel, which prevented fresh water reaching sea, succession of depressions brought period of wet weather that lasted for several weeks
Somerset Levels Floods: Social Impacts
16 farms evacuated, 600 houses flooded, many people had power supplies cut off
Somerset Levels Floods: Economic Impacts
1,000 livestock evacuated, 14,000 hectares of agricultural land underwater for 4 weeks, local roads cut off by floods
Somerset Levels Floods: Environmental Impacts
Huge amount of debris had to be cleared, floodwaters were heavily contaminated with sewage + other pollutants e.g oil + chemicals, stagnant water that had collected for months had to be re-oxygenated before being pumped back into rivers
Somerset Levels Floods: Immediate Responses
Villages cut off by floods used boats to go shopping or attend school, local community groups + volunteers gave invaluable support
Somerset Levels Floods: Long-term Responses
8km of River Tone + Parratt were dredged, Road levels + river banks were raised, more pumping stations were built
Causes of increasing extreme weather in the UK
Climate change as it causes there to be more energy in atmosphere, which could lead to more intense storms + atmospheric circulation may be affected, bringing floods to normally dry regions + heatwaves to normally cooler areas
Depressions
Areas of low pressure
