Hazardous Earth Flashcards
Explain why low latitude locations receive more heat then places close to the poles
Earth is largely spherical so more radiation is received at the equator, the hottest part of the earth, where the poles are the coldest part of the earth
Latitude
Horizontal line;measurement of distance from the equator which ranges from 0° at the Equator to 90°
Longitude
Vertical line;measurement of distance from the equator which ranges from 0° at the Equator to 90°
How does atmospheric circulation causes high pressure areas (dry) like Tindouf
Areas of high pressure are caused by descending air from Hadley and Ferrell cells. As air cools it descends leading to high pressure at the surface. Also the air is descending, which reduces the formation of clouds and leads to light winds and settled weather conditions
How does atmospheric circulation causes low pressure areas (wet) like Singapore
Areas of low pressure are caused by ascending air from two Hadley cells. As air warms it ascends leading to low pressure at the surface. Water vapours condense forming clouds and perhaps precipitation. Weather in depression area is often unsettled
Atmospheric circulation cells
- Hadley cell
- Ferrel cell
- Polar cell
How is heat transferred
Winds blow from areas of high pressure to areas of low pressure, transferring heat away from equator
How do atmospheric circulation cells move heat around world
Winds are part of global atmospheric circulation cells. cells have warm air rising which creates a low pressure belt and cool falling air which creates high pressure be
Four different factors that cause climate to change over last 400,000 years
Orbital changes
Volcanic activity
Solar output
Asteroid collisions
Orbital stretch
Earth orbital path around sun changes from almost perfect circle to ellipse (oval shape) and back every 96000 years
Orbital tilt
Earth axis is tiled at angle as orbits sun. Tilt changes over cycle of 22000 years
Volcanic activity effect on climate
Major volcanic eruption ejects large quantities of materials,e.g ash, into atmosphere.
Some of the particles reflect the Sun’s rays back out to space, the earth gets cooler
Example if this is eruption of Mount Tambora in Indonesia in 1815 with lead to a year without summer
How do ice cores in Antartica tell us about previous temperatures
By analysing the gases (e.g carbon dioxide) trapped in the layers of ice, you can tells the temperature was each year
Greenhouse gases
Water vapor (H2O) Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) Ozone (O3)
Factors that show climate change is happening
Sea level
Since 1901 sea levels have risen by almost 0.2m.Water in the ocean expands as it gets warmer, this is called thermal expansion
Global temperatures
Temperatures have increased by nearly 1 degrees since 1880 and expected to rise by 0.3-4.8 depress between 2003 - 2100
3 consequence of climate change
Some areas in world could become so hot and dry that it can be difficult or impossible to inhabit
Lower crop yields could increase malnutrition, ill health and death from starvation, particularly in lower latitude countries
Some farmers in higher latitude countries benefit
Astroid collision impact on climate
Astroid hutting the earth’s surface can launch huge amounts of dust into atmosphere
Orbital wobble
(Also called precession) the axis of Earth wobbles like a spinning top every 2200 year cycle
How have humans enhanced greenhouse effect
Industrial
Some industrial processes also release greenhouse gases,e.g cement is made from limestone, which contains carbon. When cement is produced lots of CO2 is released
Industrial waste may end up in landfill sites where it decays, releasing CH4
Farming
Farming of livestock produces a lot of CH4
Rice paddies contribute, as flooding fields emit methane
What is Tropical cyclone
Tropical cyclones are circular in shape hundreds of kilometres wide and usually last 7-14 days
Spin anticlockwise in northern hemisphere and clockwise in southern
Center of cyclone is called eye, low pressure, no clouds, no rain and high temperature in eye
Eye is surrounded by eyewall, strong winds(around 160km per hour) storm clouds and low temperature
Formation of Tropical cyclone
Source area of most cyclones is between 5* and 30* north or south of equator, any further from equator and water isnt warm enough. When sea temperatures are 26.5*C or higher and when wind shear(difference in windspeed) between higher and lower parts of the atmosphere is low. Warm, moist air rises and condensation occurs. This releases huge amounts of energy, which makes the storm powerful. The Earth’s rotation deflects the paths of the winds which causes the cyclone to spin.
How do cyclones intensify in energy
Cyclones intensify due to energy from the warm water.
How do cyclones dissipate
When moved over land or cooler water
Tropical cyclones cause physical hazards
Wind speeds can reach 250km/h
Tropical cyclones can releases trillions of litres of water per day as rain. Rain gets heavier closer to eye
Storm surge is a large rise in sea level caused by low pressure and high winds
Flooding happens as a result of storm surges and strong winds driving large waves to shore
Tropical cyclone impact on people
People may drown in strong currents
Wind speeds in tropical cyclones can destroy buildings leaving people homeless and jobless
Damaged roads make it very difficult for aid and emergency vehicles to get through
Tropical cyclone impact on environment
Trees are uprooted by high winds which can damage or completely destroy wooden habitas
Storm surges can erode beaches and damage costal habits (e.g coral reefs)
Flooding caused by storm surges can pollute freshwater environment with saltwater
Most vulnerable to tropical cyclone
Physical
Low-lying coastlines are vulnerable to storm surge flooding as well as large waves caused by high winds
Steep hillsides may increase the risk of landslides
Economic
Poor countries are vulnerable as:
Many people depend on agriculture which is often badly affected, leading to loss of livelihood
People may not have insurance to cover costs of repairing damage and infrastructure
Social
Poor countries are vulnerable as:
Health care isnt as good for flood defence so they struggle to treat all casualties
Harder to rescue people because poor infrastructure
Solar output
Suns output of energy isnt constant. Changes in short cycles of 11 years and possibly longer cycles
Reduced solar output can change climate may causing mini ice age
Example- Maunder Minimum was a period of reduced solar output between 1645 to 1715 causing mini ice age
Convection current
When lower parts of the asthenosphere heats up they become less dense and slowly rise
As they move towards top of asthenosphere they cool down becoming more dense then slowly sink
This drags on base of tectonic plates and moves them
Convergent boundaries
Two plates are moving towards each other
Where oceanic plate meets continental the denser oceanic plate is subducted into mantle and destroyed
When two continental plates meet the plates collide and ground is folded and forced upwards to create mountain ranges
Divergent boundaries
Where two plates are moving away from each other, e.g mid-Atlantic ridge. Magma rises from the mantle to fill the gap and cools creating new crust
How is a volcano formed
A volcano is formed when magma rises from inside the earth and erupts onto the surface.
Convergent boundary
Where two plates move towards each other
If when oceanic plate meets continental plate, the denser oceanic plate is forced down into mantle and destroyed. This often creates volcanoes and ocean trenches
If when two continental plates meet the plates collide and the ground is folded and forced upwards to create mountain ranges
Divergent Boundaries
Where two plates are moving away from each other e.g mid-Atlantic ridge. Magma rises from mantle to fill the gap and cools creating cracks
Conservative boundary
Where two plates are moving in the same direction but at different speeds e.g along west coast of the USA. Crust isnt created or destroyed
Volcano formation/Divergent plate boundary
The magma rises up into the gap created by the plates moving apart forming a volcano
Volcano formation/Convergent plate boundary
Oceanic plate moves down into mantle where its melt and destroyed. A pool of magma is formed rising though vents in the crust. Magma erupts onto the surface, now called lava, forming a volcano
3 ways earthquakes occur
convergent boundary
divergent boundary
conservation boundary
What are earthquakes
Shockwaves caused by movement of plate boundaries
How are earthquakes measured
Using moment magnitude scale
