Weather Hazards Flashcards
What is the global distribution of tropical storms?
Tropical forms form 5-15 degrees north and south above the equator because at the equator, there is not enough spin from the rotation of the Earth. In tropical regions, the intense heat makes the air unstable causing it to rise rapidly.
What are the causes of tropical storms? How might climate change affect the distribution, frequency and intensity?
Distribution: sea surface temperatures in the tropics have risen 0.25-0.5 degrees. Tropical storms may affect areas outside the current hazard zone.
Frequency: rising sea temperatures give extra energy for tropical storms to form making them form more frequently.
Intensity: higher sea temperatures mean the tropical storms will be more intense as they have more energy.
What are the structure and features of a tropical storms?
Central eye is a small area where cold air sinks towards the ground and warms up. There are no clouds here and conditions are calm.
Out either side of the eye is a tall bank of cloud called the eye wall. Here there are strong winds, heavy rain, thunder and lighting.
Beyond the eye wall are banks of clouds with thunderstorms and sometimes tornadoes. There will be strong winds and heavy rain.
Describe the sequence of their formation and development
Strong upward movement of air draws water vapour up from the warm ocean surface. This evaporated air cools as it rises and condenses to form thunderstorm clouds. As the air condenses it releases heat which powers the storm and draws up more water.
Several smaller thunderstorm clouds join together to form a giant spinning storm. The storm develops an eye at its centre where air descends rapidly. As the storm is carried across the ocean by prevailing winds, it continues to gather strength. On reaching the land the storms energy supply is cut off and friction with the land slows it down and it begins to weaken.
What are the primary and secondary effects of tropical storms?
Primary: 6300 killed - most drowned. 600000 displaced and 40000 homes destroyed - 90% of tacloban destroyed. 30000 fishing boats destroyed and strong winds damaged buildings and power lines. 400mm of rain causes widespread flooding.
Secondary: 14m people affected, 6m lost source of income. Flooding causes landslides and block roads, cutting off aid. Power supples cut off for a month in some areas. Shortages of necessities lead to outbreaks of disease.
Name the Immediate and long-term responses
Immediate: 1200 evacuation centres were set up to help the homeless. UK government sent shelter kits. US aircraft carrier George Washington assisted with search and rescue and delivery of aid.
Long-term: UN and other counties donated aid. Cash for work programs. Rice farming and fishing quickly re-established. Homes built away from hazard zones.
How does monitoring, prediction, protection and planning reduce the effects?
Protection: Windows, doors, roofs reinforced to strengthen buildings to withstand stronger winds. Sea walls built to protect against storm surges. Storm drains contracted to prevent flooding.
Planning: Raising individual and community awareness. People need to understand the potential dangers and be able to respond.
Prediction: Hurricane watch advices hurricane conditions are possible. Hurricane warning advices hurricane conditions are expected.
An example of a recent extreme weather event in the UK to illustrate: • causes
• social, economic and environmental impacts
• how management strategies can reduce risk.
Succesion of depression driven across the Atlantic Ocean brought 350mm to fall in January and February, 100mm above average.
Social: 600 houses flooded, 16 farms evacuated, moorland and muchelney villages cut off. Many people had power supplies cut off
Economic: £10M damage, 14000 ha of agricultural land under water for 3-4 weeks, 1000 livestock evacuated, Bristol to taunton railway line closed at Bridgewater.
Environmental: Floodwaters heavily contaminated with sewage and other pollutants, stagnant water had to be reoxygenated before being pumped back into rivers.
Managing: Vulnerable communities have flood defence , road levels raised, river banks raised and strengthened.
What is the evidence that weather is becoming more extreme in the UK?
December 2015 was wettest and warmest month ever recorded, severe flooding in 2013-14 caused river thames to burst banks.
What is the Evidence for climate change?
Glaciers: may disappear by 2035, artic sea ice has thinned by 65%.
Sea level: average sea level risen by 10-20cm in 100 years
Seasonal changes: natural seasonal activities are advancing, 65 species nested 9 days earlier than the 1970s
What are the natural factors of climate change?
Eccentricity: circular to elliptical orbit ever 100,000 years
Axial tilt: earth tilts between 21.5 - 24.5 every 41000 years
Precession: earth wobbles every 26000 years, causes very long days and very long nights.
When sunspot activity is at maximum, sun gives off more heat, at minimum it gives lower temperatures to earth.
Volcanic ash can block out sun, reducing temperatures on earth
What are the human factors of climate change?
CO2 - 60% of enhanced greenhouse effect. Burning fossil fuels, car exhausts and deforestation.
Nitrous oxides - 300x more effective at capturing heat. Car exhausts, power stations, sewage treatment, agricultural fertilisers.
Methane - 20% of enhanced greenhouse effect. Farm livestock, burning biomass, decaying organic material, rice farming.
How can mitigation manage the impacts of climate change?
Using renewable resources such as solar, wind, tide, nuclear and hydro-electric don't emit CO2 emissions. CO2 form fossil fuel burning is captured, transported and injected into depleted oil and gas fields as a liquid. Kyoto protocol (2005) - 170 countries agreed to reduce carbon emissions by 5.5%. 2009 - financial support for developing nations to help them cope with impacts of climate change. 2015 - 195 countries agree to peak greenhouse gas emissions, keep temp below 2 and limited to 1.5, donate $100B to support climate change initiatives in developing countries.
How can adaptation manage the impacts of climate change?
Introduce drought resistant strains of crops.
Educate farmers in water harvesting.
Shade trees planted to protect seedlings from strong sunshine.
