Topic 1 - Cylcones + Case Study + Climate Changes (set A)✔️ Flashcards
Where is most radiation received and why?
Earth is largely spherical so more radiation received at the equator - hottest part of earth
Why is the equator the hottest part of earth?
Because the earth is spherical - most radiation is received at the equator - suns rays are concentrated over a small area - strikes at a right angle - also at the poles radiation as to pass through more atmosphere resulting in most energy being absorbed
What is low pressure? What causes it?
Low pressure is a result of less air at the surface and caused when air is heated and it rises (because it is less dense) - when rising it transfers energy to the atmosphere - cools, condenses and form clouds - causing rain
What is high pressure? What causes it?
High pressure is when there is more air at the surface - caused when air cools and becomes more dense - it falls transferring heat to the ground -leaves clear sky’s and little/no rainfall
What is atmospheric pressure?
Is the weight of the air and the force it exerts on the ground
What causes winds?
Winds caused when air moves from high to low pressure across the earths surface transferring heat away from the equator
What is the Coriolis effect?
The deflection of winds from the right in the northern hemisphere and left in the southern hemisphere - caused due to the earths rotation
What are the three cells in each hemisphere?
-Hadley
-Ferrell
-Polar
Explain global atmosphere circulation cells ?
1) equator warmed by sun - causes air to rise - creating a low pressure belt (high rainfall)
2) cool dry air moves out to 30 degrees north and south of equator
3) at 30 degrees - cool air sinks creating high pressure belt (low rainfall)
4) cool air reaches ground surface and moves as surface winds back to equator or towards the poles
What are surface winds that blow towards the equator called?
Trade winds blow from SE in southern hemisphere and NE in northern hemisphere - meet at equator and are heated by the sun - causing them to rise and form clouds
What are westerlies?
Surface winds that blow towards the poles - blow from NW in southern hemisphere -and SW in northern hemisphere
What are ocean currents? Give an example of an ocean current?
Large scale movements of water that transfer heat energy from warmer to cooler regions (can be surface currents or deep ocean currents) - example of current is golf stream heats Europe with warm water from Caribbean
What happens to colder and freezing water? What does it cause?
Cold water freezes at the poles - surrounding water gets saltier increasing its density - it sinks causing warmer water to flow at the surface - creating a current - warmer water cools and sinks continuing cycle
What is thermohaline circulation?
The cycle of cooling and sinking water moving in a big loop round the earth
What are ITCZ - Inter tropical convergence zones?
Permanent zones of low pressure with high rainfall - occur near equator between Hadley cells
Why do ITCZ have high rainfall?
They occur near the equator between two Hadley cells - where warm tropical air flows to the equator from the north and south - intense radiation from sun causes air to rise, expand and become less dense - resulting in low pressure and lots of rainfall
What are orbital changes and what do they cause?
Changes and variations in the way the earth moves around the sun (orbit) - changes may have caused glacial and interglacial periods
What is stretch/eccentricity and what does it cause?
Changes in the earths orbit - happens over a long period (100,000 years) - sometimes earths cycle is more circular around the sun making it warmer (interglacial) - sometimes its more elliptical making earth cooler(glacial)
What does changes in Axial tilt cause?
Earth is tilted which creates our seasons - about every 40,000 years - tilt changes - earth is tilted further from sun (makes difference in seasons more pronounced) - tilted closer, difference in seasons is less
what is precession? What does it cause?
Earth wobbles when it rotates - direction axis is facing changes - affects our seasons creates either small or greater differences between summer and winter - happens over a period of 24,000 years
What is a glacial period?
Glacial period - caused when summers are cooler than they usually are - snow/ice does not melt
How can asteroid collisions cause change in the climate?
When asteroids impact with the earth the eject large volumes of dust into the atmosphere partially blocking out solar radiation - causing a decline in temperature
How can volcanic eruptions cause climate change?
Volcanic eruptions send ash and sulphur dioxide into the earth stratosphere stopping some of the suns rays heating the planet - as they are reflected of the large blanket of ash and gas
How can sunspots cause climate change?
Lots of spots on the sun indicates it is more active than usual - more solar energy being fired out - less spots shows the sun is less active and could cause cooler temperatures on earth
How are tree rings - evidence for climate change?
Each ring shows a year of growth - changes in shape and size of rings shows changes in condition that year - bigger tree ring show warmer and wetter conditions
How do ice cores show climate change?
Ice contains bubble of air from that year - each layer shows scientists how much co2 they contain and they can also learn about temperatures for each year
How do historical sources show evidence of climate change?
Old photos, drawings, written records, dates of harvests ext - give us some insight but are not very accurate as they were not intended to record climate change
What is the greenhouse effect?
The greenhouse effect involves gases which help retain heat in the atmosphere - it is needed for life on earth as it warms the planet
How does agriculture cause enhanced greenhouse effect?
- trees absorb and store CO2 - more trees cleared for cattle farming, rice paddies, housing - less absorption of CO2
- greater demand for food - more rice paddies which produce lots of methane
How does energy cause enhanced greenhouse effect?
Demand for electricity is growing due to increased in population and new technologies - most energy produced through fossil fuels which produce greenhouse gases
How does transport cause enhanced greenhouse effect?
- more vehicles being used which run on fossil fuels - release greenhouse gasses when burnt
- car ownership increasing among developing countries eg china so more cars on the road - increasing congestion and resulting in engines running longer
How does industry cause enhanced greenhouse effect?
Industry uses lots of energy and releases greenhouse gases eg cement made from limestone which releases lots of carbon dioxide - industrial waste may end up in landfill where it decays releasing methane
What is the eye of cyclone? What are the features of the eye?
Central part of the tropical storm - usually between 30 - 50 km across - area with light winds and no rain - surrounded by large cumulonimbus clouds caused by moist air condensing as it rises
What decides how intense a tropical cyclone will be?
The temperature of the water - warmer will fuel a more intense cyclone
Explain stage 1 of the formation of tropical cyclones?
1) Warm air rises from the ocean which leaves an area of low pressure below - this space is instantly filled by surrounding air rushing in - causing strong winds
Explain stage 2 of the formation of tropical cyclones?
2) The air that has rushed in now warms up and rises too - rising air brings with it moisture which cools and condenses to form towering storm clouds - This forms the eye wall
Explain stage 3 of the formation of tropical cyclones?
3) When the cooled air descends it will form an area of calm in the centre called the eye
Stage 4 of formation of tropical cyclones?
4) Due to the winds near the equator the tropical storm starts to move from east to west -the spin of the Earth causes these winds to curve and leads to the storm starting to spin
Temperature of water for cyclone to form?
26.5 degrees - normally in warmer months
Where do tropical cyclones form?
Start within 5 and 30 degrees north and south of the equator where surface temperatures exceed 26.5 degrees
4 main hazards or tropical cyclones?
- high winds
- intense rainfall
- costal flooding and storm surges
- landslides
How are high winds from tropical cyclones dangerous?
Tropical cyclones produce winds of 119 up to 250 km per hour - can uproot trees and can damage infrastructure like power cables and can blow down poorly built buildings
How is intense rainfall from tropical cyclones dangerous?
When cyclones move over ocean take up large amount of water which is released as rain can cause flooding which damages property and cause deaths
How are storm surges formed?
Cyclones creates a large area of low pressure which allows the level of sea to rise combined with high winds results in a large mass of water forced towards land
How are storm surges from tropical cyclones dangrous?
Hits land with severe force - erodes beaches and costal habitats, damages coastal defences , contaminates farmland and freshwater lakes ext.
How is costal flooding from tropical cyclones dangerous?
Combination of intense rainfall and storm surges can cause flooding which can damage property, infrastructure, farming and tourism - salt water is dangerous for the environment
How are landslides caused by Tropical cyclones?
High levels of rain can saturate the soil very quickly which makes the soil heavy and in areas of steep slopes means the soil can no longer hold its position and will slide down the slope - destroying infrastructure and settlements nearby
4 main Impacts on people from tropical cyclones?
- people drown due to storm surge and flooding
- winds can destroy buildings making people homeless
- electric supplies and communications are cut off when cables damaged by wind
- shortage of clean food and clean water
4 main Impacts on the environment from tropical cyclones?
- trees uprooted - loss of wooded habitats
- storm surges - erode beaches and damage costal habitats
- landslide - deposit sediment in rivers and lakes killing water life
- flooding can damage industrial building causing oil leaks and pollution
What is Saffir-Simpson hurricane wind scale?
Saffir - Simpson hurricane wind scale is a 1 to 5 rating based on hurricanes ,maximum sustained wind speed
Three strategies to prepare and respond to tropical cyclones?
- forecasting
- evacuation
- defence
How can a cyclone be forecasted?
Weather forecasting and satellite technology to monitor and predict the path of the cyclone
How can people be evacuated before a cyclone hits?
early evacuation routes can be planned and people can be altered hours or even days before it hits - rescuers can be trained at rescuing people from flooding ext
How can defences stop/minimise damage from cyclones?
Sea walls can be built to protect from storm surges - buildings can also be built on stilts so they are safe from flood water
Impacts on the enviorment from hurrican katrina (2005)?
-costal habitats - sea titles beaches destroyed
-half of national wildlife destroyed
-flooding causes oil spills from refineries
Impacts on people from hurrican katrina (2005)
- 1800 killed
- 300,000 houses destroyed
- 3,000,000 without electric
- infrastructure damaged/destroyed
- 230,000 jobs lost
Impacts on the environment from Cyclone Nargis(2008)?
- 14,000 km land flooded
- 38,000 hectares of mangrove forest destroyed
- flooding caused erosion and salination of the land
What is salination and what does it cause?
Is increased salt content in the ground and makes it extremley hard to grow crops
Impacts on people from Cyclone Nargis(2008)?
- 140,000 dead
- 450,000 houses destroyed
- 350,000 houses damaged
- 65% rice paddies damaged
- lots of diseases
Forecasting for Cyclone Nargis(2008)?
- Myanmar does not have a dedicated monitoring centre - cant predict height of storm surges
Forecasting for Hurricane Katrina(2005)?
- US has sophisticated monitoring system to predict when hurricane would hit - had satellite imaging
Give evidence that show human activity is causing climate change?
Eustatic sea level rise - warmer temperatures are causing glacier and ice sheets to melt - water stored in the ice is returned to the ocean
Effect or warm water in regard to sea level rise?
Warm water takes up more space as it expands - thermal expansion
explain the features pf each category for the Saffir-Simpson hurricane wind scale?
Category 1 - storm surge 1.5m - some damage
Category 3 - storm surge 3.4m - major damage to well built homes
Category 5 - storm surge > 5.5m - many buildings destroyed
