Hazardous Earth Flashcards
Global atmospheric circulation
Movement of air around the atmosphere.
Anticyclone
Area of high atmospheric pressure where the air is sinking
What do anticyclones bring in the summer
Dry hot weather
What do anticyclones bring in the winter
Clear skies, frost and cold nights, light winds
May also bring fog & mist due to condensing cold air
Low pressure
Rising& unstable air, CCC( cools, condenses, clouds)
High pressure
Sinking & stable air, clear skies
Why is the equator hotter than the poles?
There’s a higher concentration of sunlight due to the earth’s tilt and spherical shape. Both the poles and the equator have an equal amount of sunlight, just over different size surface areas.
Why is there rainforests on the equator?
Because low pressure weather systems there lift up air so it CCC, creating a tropical climate.
Where’s the Sahara desert?
North of the equator and the Sahel (rainy climate).
What drives global circulation
Intense heating from the sun on the equator
0 degrees air pressure
Low
30 degrees air pressure (n&s)
High
60 degrees north and south air pressure
Low
Poles air pressure
High
Hadley cell
The convection current of air formed by rising warm air on the equator and cooling, sinking air at the tropics. It’s thermally direct.
Ferrell cell
Motion of air in the midlatitudes, sinking air in the tropics combined with rising air from the poles. It’s thermally indirect.
Polar cell
Sinking air from the poles is combined with the rising air at 60 degrees.
Westerlies
Air pulled towards the poles
North and southeast trade winds
Surface air flowing from 30 degrees north and south to the equator, due to rising air at equator.
Coriolis effect
Spin of the earth and how it affects the trade winds to curve. Right in the northern hemisphere and left in the southern.
Cells
Air currents such as Hadley, Ferrell and polar
Jet streams
Air currents between cells, narrow bands of strong air currents circling the globe 6-14 km off the ground.
Purpose of air and water currents
They regulate our global temp
Rising water
Warm, light water
Sinking water
Cold, salty and heavy water
What does water do at the equator?
It rises and spreads towards the poles
Ocean currents
Movements of surface water
How much of the earths surface does water take up?
67%
Current loops
Gyres
Current flow direction in north
Clockwise
Current direction in south
Anti-clockwise
What affects ocean currents
Wind on the ocean surface Size of the oceans Trade winds Coriolis effect Uneven heating Salinity Ocean floor shape
Gulf Stream location
SW of England, E of Canada & America, in North Atlantic Ocean
What’s the Gulf Stream driven by
Surface wind patterns and water density
What’s water in the North Atlantic cooled by and what’s the effect of this?
Arctic winds (north east trade winds) from the north cool the water, causing it to sink and replace water that then travels back to the equator. This drives warm currents into the Gulf of Mexico to be warmed to 30°C and be transported into North Atlantic onto Europe.
What happens to the ocean currents at the equator?
Water is evaporated due to high concentration of sunlight, this means the water has high salinity but isn’t too dense due to its high temp.
Where does the Gulf Stream carry water?
Warm water is moved from the Gulf of Mexico to the North Atlantic.
How much warmth does it bring to the UK and NW Europe?
5°C
What happened after our last ice age that affected the Gulf Stream?
An iceberg melted in the USA, causing a reduction in the salinity of the ocean and therefore of the Gulf Stream. This reduced NW Europe’s temp by 5°C.
What’s the intertropical convergence zone?
Where trade winds meet and solar energy causes the air to rise. It’s also a low pressure zone that creates a rainy season.
Where does the ITCZ migrate to in summer?
30° north
Where does the ITCZ migrate to in winter?
30° south
Where does the ITCZ generally move?
In between the tropics
What happens after the ITCZ moves away?
A dry season is created
Jetstreams
Very strong winds in the high parts of the atmosphere
How are jet-streams created?
When cold and warm air meet and are affected by the Coriolis effect.
How fast can jet-streams get?
200mph
How high up are jet-streams?
5-7 miles up
How long can they be
Thousands of miles long
How wide can they be?
Hundreds of miles wide
Where do jet streams flow?
West to East/ North to south
What boundaries to jet streams follow?
Boundaries between hot and cold air, also high and low pressure systems
What happens to the hot and cold air boundaries in winter?
The contrast between hot and cold is greater, meaning stronger jet streams. Greater the contrast, stronger the jet stream.
Where are jet streams formed?
In the upper troposphere
How does the Coriolis effect affect jet streams?
They try to flow from high to low pressure systems but Coriolis makes them flow East.
Troposphere
Lower region of the atmosphere, bordering the stratosphere
What do jet streams bring to the UK (low weather system)?
Depressions
Depression
An area of low atmospheric pressure which produces cloudy and rainy weather
Where do depressions often begin?
In The Atlantic to be brought to the UK.
What happens at the warm front?
Tropical maritime air meets polar maritime air and rises over it. As it rises, it CCC which creates steady rain, drizzle and then clear skies w high clouds.
What happens as the warm front passes over?
A short period of clear, dry weather
What happens when the high pressure air undercuts the warm air?
High winds and cold temperatures occur while the warm air CCC which creates thunderstorms.
What happens after the cold front moves east?
Clear skies
What’s the opposite of a depression?
Anticyclones
What are the climate change theories?
The eruption theory, asteroid collisions, sunspots, the orbital theory and glacials
What’s the eruption theory?
Release of ash and sulphur dioxide into the stratosphere from a powerful eruption. Sulfur dioxide and sulphate aerosols reflect/ absorb some of the suns thermal and solar energy. Also absorbing IR radiation that would usually be reflected by greenhouse effect, further lowering earths temp.
How long does the eruption theory last?
Up to 3 years
When was the last significant eruption?
Mount Pinatubo in 1991 which lasted 2 years.
What’s the asteroid collision theory?
When large asteroids (1km) collide w earth, sending tonnes of ash and dust into the atmosphere. Basically same effect of volcanic theory. It happens every 500,000 years.
How long do the effects of the asteroid theory last?
5-10 years
What’s the sunspot theory?
Cycles reappearing black spots on the suns surface that emit more energy and so increase the temp of the earth.
What’s the orbital theory
The 3 Milankovich cycles: eccentricity, axial tilt, precession.
What’s eccentricity?
Change in orbit
What’s axial tilt
Change in tilt
What’s precession?
Wobble of the axis
How long can the effects of milankovich cycles last
Thousands of years
Glacial period
Ice age
Interglacial period
Non glacial points
Geological time
Processes that occur over a very long time (millions of years). DISTANT PAST
Historic time
Describes particular major events thought to have happened at a time. RECENT PAST
How do you measure past climates?
Tree rings, ice cores or historic evidence
How do tree rings show past climates?
Width of the tree rings convey how much rainfall, the temp and extremities that year. A new tree ring grows each year. It can give us 2000 years of info
How do ice cores show past climates?
They preserve volcanic ash and air bubbles from up to 1.5 million years ago. You can see the amount of CO2 in the air at the time, correlating with the temp.
Which historic evidence shows past climates?
Diaries, paintings and newspapers
Shortwaves
Lift from the sun
Long waves
Light from the earth
How much does the greenhouse effect warm our earth by?
32°
Name all greenhouse gases
CO2 (89%), halo carbons (1%), methane (7%)
Where does CO2 come from?
Industry, farming, burning of fossil fuels
Where do halo carbons come from being the most damaging?
Aerosols and fridges
Where does methane come from?
Farming
Impacts of climate change
Environmental refugees, sea levels rising, currents changing, animal extinction and unpredictable weather
By 2050, how many environmental refugees will there be?
150 million
Why do people living in the Maldives need to leave?
Rising sea levels and acidification of coral
Why are sea levels rising?
Expansion and melting of ice
Why are currents changing?
Melting ice caps, fluctuating sea temps and lowering of salinity
Why are animals going extinct?
Deforestation, rising sea levels, soil and sea acidification, extreme weather, temp rise not allowing them to adapt
Why is unpredictable weather occurring?
Flooding (rising sea levels), droughts (temp increase), hurricane (temp increase suits conditions for a hurricane)
Why are scientists so uncertain about the future?
Population, renewable energy prices/ efficiency, economies, fossil fuel stores, deforestation
Positive feedback mechanisms
How we are stuck in a spiral of unrenewable energy
Acronym for reasons why climate change is real
SHEEP (social, historical, economic, environmental, political)
Name 3 types of storms
Typhoon, cyclone, hurricane
Typhoon
Storm in the Pacific
Cyclone
Storm in the Indian Ocean
Hurricane
Storm in The Atlantic
What wind speed do they need to be to classify as a tropical storm?
74 mph
Impacts of tropical storms
Heavy rain, strong winds, storm surges, pressure drops, flooding
What temp do oceans need to be for tropical storms?
26°C and over
What do tropical storms gain energy from?
Warm oceans and moisture
What pressure do tropical storms form in?
Low
Where do they form?
8-20° north of the equator where the easterly trade winds meet
Why do tropical storms spin?
Coriolis effect
What’s the center of a storm called?
The 👁 eye ( completely calm)
Where are tropical storms most destructive?
The eyewall
How do tropical storms form?
26°C ocean evaporates water into air, creating a low pressure system. As it rises, it CCC generating huge amounts of energy which fuels it. When air reaches the top it flows outwards and down ready to be heated again. The Coriolis effect spins it.
Where do tropical storms move?
In a westerly then northerly direction
What do you need for a storm surge to occur ?
Low pressure, high tides and strong winds
How do storm surges form?
Zones of rising air lift weight off the oceans surface creating a bulge which is pushed by strong winds towards the coast. It’s affected by the topography of the land.
Secondary impacts
Impacts of a hazard
Secondary impacts of tropical storms
Property damage, damage to flora and fauna, flying debris, fast moving water, contamination of drinking water,landslides
Vulnerability
The diminished capacity of an individual/ group to anticipate, cope with, resist and recover from the impact of a natural/ man made hazard. Physical social and economic
Example of physical susceptibility
Coastal areas are more exposed to tropical cyclones rather than inland areas/ landlocked countries. Relief affects your vulnerability from wind, rain, flooding & landslides.
Example of social susceptibility
Areas of poverty are mores susceptible due to poorer housing and lack in supplies/ preparation. Areas with high dependency populations are more susceptible as these are harder to evacuate. If you don’t own a car then you it’s harder to evacuate and so you are more vulnerable.
Example of economic vulnerability
Having technology means that you can anticipate and prepare for these natural hazards, wealth affects the country’s ability to cope/ make well-established evacuation plans.
Layers of the earth
Crust, upper mantle, asthenosphere, lower mantle, outer core, inner core
What’s the lithosphere made up of
The crust and upper mantle
What’s the crust made out of
Silicon based rocks. Continental (granite) and oceanic (basalt).
Characteristics of continental crust
Older, thicker, less dense and so lighter. 45-50 km thick
Characteristics of oceanic plates
Thinner, younger, more dense and so heavier. 6-10 km thick
What’s the mantle made up of
Silicon based rocks. Lower mantle, asthenosphere, upper mantle. Molten/ semi molten magma.
What’s the asthenosphere?
Upper part of the mantle upon which the plates shift
What’s the core made out of?
Iron and nickel
Characteristics of the core
4400°C-6000°C
Inner is solid due to center of gravity and outer is liquid.
Why do convection currents occur in the mantle?
Radioactive decay of elements like uranium in the mantle/ core produce heat, making magma become less dense and rise before cooling and sinking back down again. This forms circular movements.
How do convection currents move tectonic plates?
They create drag on the base of the tectonic plates.
Who proposed the continental drift theory and when?
Alfred Wegener at the beginning of the 20th century, based on similar species/fossils on far continents.
What is the theory of continental drift?
The theory that 250 million years ago, there was one supercontinent called PANGEA. Convection currents then caused it to split into Gondwana land & Laurasia before it formed what it now is today.
What are the names of all the plate boundaries ?
Convergent, divergent and transform
What is a convergent plate boundary?
When more dense oceanic plate is being forced under (subducted) the less dense continental. Friction causes melting of the oceanic plate. These create ocean trenches, volcanoes, tsunamis or earthquakes. Eg: the Nazca plate under the S American plate
What is a divergent plate boundary?
(Constructive) when plates move apart, causing magma to well up and harden. Can form volcanoes. Eg: the mid-atlantic ridge.
What’s a transform plate boundary?
(Conservative) when plates slide past each other in opposite directions or at different speeds. Friction is eventually overcome, forming a sudden movement that further creates shockwaves leading to earthquakes. Eg: San Andreas fault in California.
Where do volcanic hazards occur at?
Convergent and divergent plate boundaries or hot spots.
What are hot spots?
They are found on the interior of tectonic plates when a magma plume from the asthenosphere breaks/melts the rock in the lithosphere. These can create volcanoes or new islands. The crust above them can shift which causes a chain of volcanic islands. Eg: Hawaii on the Pacific plate.
Where do composite (strato) volcanoes occur?
Convergent boundaries
What are the characteristics of a composite volcano?
Pyroclastic flows, steep sides, lava & ash layers, explosive and destructive, infrequent eruptions
What lava does composite volcanoes erupt?
Andesitic lava (high silica content) which is more viscous.
Why do composite volcanoes occur ?
Because oceanic crust contains water that reacts with the magma, trapping gases and therefore building pressure that causes the crust to erupt. Due to the high viscosity, andesitic lava that cant flow far, a cone shape is formed. Eg: Mount Fuji in Japan
Where do shield volcanoes occur?
At divergent plate boundaries or hotspots.
What are the characteristics of shield volcanoes?
Low, flat sides, layers of lava, less viscous lava, frequent eruptions, low explosiveness, only produce lava
What type of lava do they produce?
Basaltic lava with low silica content meaning it’s less viscous and so flows quickly, covering distance to create gentle sides.
What are the primary hazards of volcanoes?
Lava Pyroclastic flows Volcanic bombs Ash Gases
Secondary impacts of volcanoes
Acid rain Lahar (mud flows) Landslides Tourism increase Nutrients in agricultural soil Geothermal energy opportunities Destruction of landscapes
Short term relief
The immediate causes of action when a hazard strikes initially, lasting no more than a couple months.
How do you prepare for an earthquake?
Creating a good communication system (so people can evacuate) like mobile alerts and police cars to disadvantaged areas
Building earthquake proof buildings
Automatic shutters on windows (prevents falling glass)
Shock absorbers on buildings (absorb tremors)
Make evacuation routes
What makes a good evacuation center ?
Being away from the hazard, having suitable supplies and accessible
How are tsunamis formed?
Convergent plate boundaries under the sea subduction the oceanic plate, building up pressure as the continental plate is dragged downwards. A release of pressure (fault) thrusts the continental plate upwards, displacing and lifting water which creates a wave. As they hit shallower sea, the waves become bigger due to a shorter trough.
Human factors affecting vulnerability to tectonic hazards
Knowledge (education), economy (money invested in relief), population, government, structural integrity
Physical factors affecting susceptibility to tectonic hazards
Distance from epicentre, focal depth, geology, relief of land, magnitude of quake
Chloropleth diagram
A map that displays regions of color
Where does wind blow?
High to low pressure
How do you measure earthquakes?
Seismometers
