topic 1 - hazardous earth Flashcards
describe the global atmospheric circulation ?
- air circulates around the -hadley cell
- air rises from the equator which is the hottest part of the earth
- leading to low pressure and high rainfall
- when the air reaches the edge of the atmosphere is moves 30 north and south
- and the air becomes cooler and denser which causes the air to sink creating high pressure with cloudless skies and little rainfall
- cool air reaches the ground surface and moves as surface wind back to the equator or towards the poles
- air rises again at polar cell 60 n/s of the equator creating low pressure belt . at the poles the cool air sinks creating high pressure and moves back to the equator as surface wind
at the equator
air circulates around the hadely cell
the air rises from the equator which is the hottest part of the earth surface
leading to low pressure and high rainfall
the air begins to cool and becomes denser causing it to sink
at 30 north and south
the rising air cools and sinks and moves away from the equator towards 30 north and south creating high pressure and cloudless skies with little rainfall
at 60 north and south
when the cool air reaches the earths surface it moves as surface wind either towards the equator or towards the poles air rises again a the polar cell forming low pressure
at the poles
at the north and south pole the cool air will sink forming high pressure belt , this high pressure belt will move back to the equator as surface wind
hadley cell
the ground is heated causing the air to rise
the rising air forms low pressure eventually cools and condenses forming clouds
climate
hot due to the sun ray being most intense near the equator
high rainfall
eg tropical forest
ferrel cell
occur at high latitude ( 60 n/s )
the warmer surface wind meet the cold air from the poles
the warmer air rises as it is less dense then the cold air
creating low pressure
climate cold and wet
the polar cell
the air is cooled and sinks towards the earth surface
forming high pressure
climate little rainfall
low pressure
the warmth of the earth surfaces heats the air above
which causes the air to rise
as it rises it cools and condenses forming clouds
low pressure belt - high rainfall eg rain forest
high pressure
when cool and denser air sinks back down to the earth surface
resulting in high pressure belt
- little rainfall
- cloudless skies
- arid areas
- eg deserts
types of ocean currents
deep ocean current - caused by the difference in water density
surface ocean - caused by winds , transfers heat from the equator to cooler regions
volcanic activities
volcanic eruption releases lots of volcanic material into the atmosphere which can block the sun’s ray which causes the earth climate to be colder
sunspot
sun spots are black spots on the earth surface , they increase the suns output energy resulting to warmer climate
orbital change
the earth has a natural warming and cooling period caused by the milankovitch cycle , this depends on the way the earth moves around the sun . when the earth is further away from the suns solar radiation is reduced resulting in cooler climate
natural factors that are potential causes of climate change
volcanic activity
asteroid collision
sunspots
orbital changes
human factors that causes climate change
farming transportation industry energy deforestation
farming
livestock produce a lot of methane which is a greenhouse gas
rice paddies emit lots of methane gas
deforestation - fewer trees to absorb c02 from the atmosphere to use in photosynthesis
transportation
cars burn fossil fuels. carbon emissions get released into the atmosphere so the amount of greenhouse gases released increase
energy production
fossil fuels including coal and oil and gas , when fossil fuels get burned c02 is released
evidence that human activity is causing climate change
declining arctic ice
sea level rise
extreme weather events
global temperature rise
extreme weather events
extreme weather such as droughts , heatwaves etc will become more frequent and extreme
declining arctic ice
the arctic ice in the winter is decreasing
global temperature rise
the temperature of the earth is increasing some areas will experience droughts
the greenhouse effect
the atmosphere allows heat from the sun (short wave radiation ) to pass through to heat the earth surface
the earth surface absorbs some of this radiation but then gives off heat long wavelength radiation is reflected back into the atmosphere
This heat is trapped by the greenhouse gases which radiates heat back towards the earth
reduced biodiversity
reduced biodiversity
the rate at which climate change is changing is making it difficult for animals to adapt to the habitats which could lead to extinction
effects of climate change on the environment
reduced biodiversity
melting ice
change in precipitation pattern
melting ice
melting ice is causing sea level to rise which could lead flood coastal habitats
effects of climate change on humans
lower crop yields
more death due to heat
extreme weather events
Loss of coastal areas
lower crop yields
climate change might increase temperature so it would make it harder to grow crops. People could die from starvation
evidence for natural climate change
ice cores
tree rings
Historical records
pre-condition of a tropical cyclones
sea temperature above 26 c or warmer
this leads to warm air to rise forming low pressure
location within 5-30 degree north and south where the Coriolis effect is strongest to make it spiral
sea depth 70m and above
explain 2 reasons for the range of projections
one reason for the projection in climate change is due to the uncertainty of population growth in the future . If the population growth decrease this may lead to less global warming another reason is the energy source . If humans use non-renewable energy this would increase global warming
formation of tropical cyclones
tropical cyclones form when the sea temperature reaches 26 c and above. It’s causes the air above to rise which realises huge amount of energy which creates powerful storms and rapidly rising air . Trade winds at the equator causes the storm to spiral upward due to the Coriolis effect . The eye is created as cooler air sinks and cumulonimbus clouds form an eye wall . The cyclone begin to dissipate as it reaches land or cooler water
features of tropical cyclone
eye wall - spiralling rising air , very strong wind ,low temperature
Centre - low pressure , high temperature , no clouds or rain
circular shape
physical hazards of tropical cyclone
intense rainfall storm surge high wind coastal flooding Landslide
where are low pressure belt found and where does the air go
low pressure belts found at the equator and 60 n/s of the equator
air rises
where does high pressure belts occur and where does the air travel
high pressure belts found at the poles and 30 n/s
air sinks
tropical storms are rated on the
saffir-Simpson scale - based on wind speeds
tropical management strategies
reducing the impacts of tropical cyclones
forecasting
evacuations
defences
some countries are more vulnerable than others due to
social vulnerability
economic vulnerability
physical vulnerability
social vulnerability
low income counties are more socially vulnerable this is because they usually have poorer quality material and poor healthcare system and have less money spend on defences .
economic vulnerability
poorer countries are economically more vulnerable this is because most of the population work in agriculture which can often be badly affected eg flooding
layers of the earth
crust
mantle
outer core
inner core
crust
also know as the lithosphere thin outer layer 60km thick solid layer made up of granite and basalt
2 types of crust
oceanic and continental
difference between the oceanic an Continental crust
oceanic crust continental crust
more dense less dense
thinner thicker
mantle
thickest layer
layer which surrounds the core
made up of semi-molten rocks or magma
mantle can be split into 3 sections
the upper part of the mantle is solid
middle layer known as the asthenosphere is semi molten
outer core
liquid layer
made from nickel and iron
inner core
centre of the earth
hottest part of the earth
solid layer
very dense
explain how convection currents move the earths surface (4 marks )
the earth core is heated due to radioactive decay
this causes the magma in the mantel to heat up
the heated magma rises to the surface of the earth as it is less dense
when it reaches the crust it moves sideways
then drags the plate apart creating a circular movement
name the 3 plate boundaries
convergent ( destructive )
divergent ( constructive )
conservatives
divergent plate boundaries
example
when 2 plates move away from each other this causes a gap between the plates. the magma rises from the mantle to sill the gap forming shield volcanoes
for example the mid-Atlantic
conservative plate boundary - 2 types
plate slide past each other in opposite directions
the 2 plates would get stuck
the friction and pressure builds up and eventually the plates slip past in a sudden movement
or
2 plates move in the same direction but at different speed
when the plates move side by side
they can get stuck together
pressure builds up
and released as earthquakes
which plate boundary forms and does not form volcanoes and earthquakes
divergent - shield volcanoes
conservative - no volcanoes but serve earthquakes
convergent - earthquake or volcanoes
convergent / collisions boundaries
when 2 plates move towards each other this caused the oceanic plate to be subducted beneath the continental plate
or
when Continental plates collide and form fold mountains
hot spots
occur where hot magma from the mantel moves towards the surface . the rising hot magma break through the crust and reaches the surface causing eruptions / forming volcanoes
how do volcanoes form on the convergent plates
when the denser oceanic plate gets subducted beneath the continental plate the friction and pressure builds up and causes a ( cracks ) vent the magma rise to the surface of the earth
characteristics of volcanoes at convergent plate margins
composite volcanoes highly explosive produces lot gas produced ashy explosions produces andesitic lava - sticky and thick
how do volcanoes form on divergent plates
when 2 plates move apart from each other the magma rises and fills the gap in between forming shield volcanoes
composite volcanoes - description
occur on convergent plate boundaries
steep-sided
explosive eruptions with ashy explosions
thick and sticky andesitic lava
shield volcanoes
occur on divergent or hotspots
not very explosive
erupt basaltic lava
low and gentle sided
Earthquakes
An earthquake is a sudden or violent movement within the Earth’s crust followed by a series of shocks.
An earthquake can happen at all 3 plate margins
At divergent margins, pressure can build up from cracks in the plates when they move apart. This can cause earthquakes.
At convergent margins, a plate can get stuck as it moves under another. This can cause earthquakes.
At conservative margins, there can be friction between plates because they aren’t smooth. This can cause earthquakes.
earthquakes can be measured using a
richter scale
features of earthquakes
focus - where the pressure is released underground and where the energy radiates out from
epicentre - the point on the earths crust that is directly above the centre of the earthquake
types of earthquakes
deep-focus
shallow-focus
deep-focus earthquakes
less damaging
occurs at convergent plates
shallow-focus earthquakes
more damaging because the shock waves have to travel further to the earths surface
tsunami
an underwater earthquake which displaces huge amount of water
