Topic 1 Flashcards
1
Q
How does the earth receive solar radiation
A
The Earth receives its radiation from the sun as radiation passes through the atmosphere and heats the ground, which heats the air above it and makes it less dense, making it rise
2
Q
How is solar radiation distributed
A
At the equator, the sun’s rays are concentrated over a small area and strike at a right angle, so temperatures are greater.
At the poles, radiation has to pass through more atmosphere and the sun’s rays are concentrated over a larger surface area since they reach the surface at a lower angle.
3
Q
What is air pressure
A
Pressure at the earth’s surface
4
Q
How is there low pressure
A
Heated air rises, transferring heat to the atmosphere as it cools and condenses to form clouds and rains - less air at the surface/pressure on the ground
5
Q
High pressure
A
Air falls as it cools due to less energy, warming the ground as it falls leaving clear skies, more air at the surface means there is high pressure on the ground, low rainfall
6
Q
Atmospheric pressure
A
The weight of the air and the force it exerts on the ground
7
Q
The Coriolis effect
A
Due to the Earth’s rotation and winds forming due to different areas heating and cooling(air moved from high to low pressure),
the wind is deflected to the right in the Northern Hemisphere and left in the Southern Hemisphere
8
Q
Low pressure belts
A
The equator - The Earth is warmed causing the air above to
rise to create a low pressure belt,
air cools and condenses, Hadley Cell
60 degrees North and South of the Equator - Between the polar and ferrel cells,warm surface winds meet colder air from poles, warm air rises creating frontal rain(when warm and cold air masses meet)
9
Q
High pressure belts
A
At 30 degrees north and south of the equator,cool air from the equator sinks(between Ferrel and Hadley cells)
At the poles, cool air sinks, air drawn back towards the equator as surface winds(polar cells). Air is returned back towards the surface of the Earth.
10
Q
Surface winds
A
When cool air reaches the ground surface and moves either back to the equator or towards the poles
11
Q
Trade winds
A
Surface winds blowing towards the equator, blow from SE in Southern Hemisphere and NE in Northern Hemisphere, at the equator these trade winds are heated by the sun
12
Q
Westerlies
A
Surface winds blowing towards the poles, from NW in Southern Hemisphere and SW in Northern Hemisphere
13
Q
What are ocean currents
A
Ocean currents are large scale movements of water that transfer heat energy from warmer to cooler regions.
14
Q
How do ocean currents form
A
When water freezes at the poles water becomes saltier increases the density, meaning it sinks and warmer water flows at the surface, creating a current
15
Q
What is thermohaline circulation
A
The cycle of water cooling and sinking due to density moving water in a big loop around the Earth
16
Q
Arid areas
A
Arid areas are mid-latitude areas(30 degrees North and South of the Equator) which receive low average rainfall(less than 250mm per year) due to high pressure. An example in Tindouf, Algeria
17
Q
Why are areas arid
A
Intense solar radiation
Sinking dry air blows outwards to block moist winds
18
Q
The Inter-tropical convergence zone
A
A permanent zone of low pressure which experiences the highest rainfall. This zone moves through the tropics taking heavy rainfall with it
19
Q
Where is the ITCZ
A
Near the equator between two Hadley cells
20
Q
Why is there heavy rainfall in the ITCZ
A
Rising air causes cumulonimbus clouds to form.
21
Q
How does the Earth’s tilt affect the Sun?
A
In June the Sun is directly overhead at 23.5 degrees north(Tropic of Cancer) and in
December at 23.5 degrees south(Tropic of Capricorn)
22
Q
What is natural climate change
A
Refers to how the average climatic conditions of the planet vary over time during the Quaternary period(last 2.6 million years)- climate has been warming since the last glacial period 15000 years ago
23
Q
How long do glacial periods last
A
100,000 years
24
Q
How long do interglacial periods last
A
10,000 years
25
How do orbital changes explain why the climate has changed in the past
The Milankovitch cycles change the Earth's orbit which affects how much radiation we receive from the Sun. These include eccentricity, axial tilt and precession.
26
How does eccentricity affect climate change
The orbit of the Earth changes shape every 100000 years,
sometimes the Earth's orbit around the Sun is more circular(meaning interglacial periods) and sometimes the Earth's orbit is elliptical(glacial periods).
27
How does axial tilt affect climate change
The angle of tilt changes every 40,000 years. The Earth is tilted
so the poles are 23 degrees from a vertical position, creating seasons north and south of the equator.The Earth is tilted sometimes away from the sun(greater difference in seasons), sometimes towards the sun(smaller difference in seasons).
28
Precession
The Earth wobbles on its axis- not perfectly rotating- on a cycle of 22000 years
29
How do asteroid collisions affect climate change
Large cosmic material like asteroids and comets releases lots of dust in the atmosphere, blocking solar radiation and leading to glacial periods
30
What do volcanic eruptions produce
Ash
Sulfur dioxide gas
31
How do volcanic eruptions affect climate change
If the ash and gas rise high enough, they are spread around the Earth by winds stopping sunlight reaching the Earth's surface, cooling the Earth.
e.g. 1815 eruption of Tambora in Indonesia, temperatures so cold harvests failed and 20,000 people died- Year without a Summer in 1816
32
How does solar output variation affect climate change
Periods of lower solar activity(detected due to the lack of sunspots-black areas - on the sun's surface) mean more glacial periods
Solar output changes in short cycles of about 11 years
Maunder Minimum was a period of reduced solar activity between 1645 and 1715 which coincided with the Ice Age
33
How do tree rings show climate change
Warmer and wetter weather shows greater growth since the tree ring is bigger,cooler or drier weather means rings are thinner
34
How do ice cores provide evidence of climate change
Scientists analyse bubbles in ice layers to see the amount of CO2 and they measure amounts of different oxygen atoms in water: to see the temperatures for each year.
35
The Little Ice Age
Between 1550-1850 temperatures were so low that rivers froze like in the London Frost Fairs
36
How do historical sources provide evidence of climate change
They give evidence of recent climate change e.g. old photos, drawings, written records
37
The Medieval Warm Period
A period of warming between 900 and 1300, with England warm enough to grow lots of grapes
37
The Medieval Warm Period
A period of warming between 900 and 1300, with England warm enough to grow lots of grapes
38
What is the atmosphere
A layer of gases above the Earth's surface
39
What is the greenhouse effect
Gases in the atmosphere trapping heat from the sun
40
Gases in the atmosphere
Nitrogen is an important nutrient for plant growth
Carbon dioxide is taken in by plants which breathe out oxygen.
Oxygen is breathed in by animals, which breathe out carbon dioxide
Water vapour forms clouds
41
How does agriculture contribute to climate change
Mechanisation means more fuel is burnt
Rice paddies(flooded field for growing crops) and farming of livestock produces methane
More CO2 in atmosphere due to deforestation
42
How does the demand for energy enhance the greenhouse effect
Greater demand for energy due to greater population/technologies:energy produced through burning fossil fuels which releases greenhouse gases
43
How transport causes the enhanced greenhouse effect
Cars, lorries, ships and planes run on fossil fuels and are used more often, so release more greenhouse gases when they are burnt
44
How industrial processes cause global warming
Greater demand for production of consumer goods leads to industrial growth. Industry uses energy, while some industrial processes release greenhouse gases(e.g. cement is made from limestone, which contains carbon).
45
How global average temperature shows increasing climate change
A large increase in average global temperature from the 1950s to the present. The ten hottest years on record have occurred since 1998.
46
How arctic sea ice shows more climate change
Arctic sea ice has melted due to warmer global temperatures.
Over 90% of the world's valley glaciers are shrinking
47
How sea level change is evidence of climate change
Since 1901, sea levels have risen by about 0.2m. This is due to eustatic sea level rise(water from melting glaciers) returning to the ocean and thermal expansion(the ocean expands as it gets warmer).
48
How extreme weather events are
evidence of climate change
Since 1950 there have been more heat waves than cold weather extremes.
December 2015 was the wettest month in the UK.
49
Impacts of climate change
More deaths due to the heat than due to the cold
Flooded/overheated areas become impossible to inhabit - meaning migration in other areas
Globally crops suffer, but in high-latitude countries crops benefit
Lower crop yields increase malnutrition, ill health and death
More money spent on dealing with extreme weather events
50
Where are tropical cyclones' source areas
In the tropics, impacted by Coriolis effect, occurs in ITCZ(zone of low pressure), away from the equator so the Coriolis effect makes the storm rotate
51
What is the eye?
The central part of the tropical storm, 30-50km across, light winds + no rain due to sinking air, wind speeds average 160km per hour around the eye, descending air, cumulonimbus clouds due to air condensing as it rises
52
What is the temperature of the ocean in a cyclone
26.5C
53
Which way do winds rotate
Winds rotate outwards at the top,
accelerating upwards and inwards
54
What impacts the intensity of a tropical cyclone?
Warmer water increases the intensith of tropical cyclone
Dissipation(losing energy) happens in areas of land/cold water/other weather systems
Tropical cyclones have lower air pressure than the air surrounding them, making the winds stronger
55
How does wind travel
From areas of high to low pressure
56
How do tropical cyclones form
1) Warm air rises and is replaced by more air which rises too
2)Water vapour condenses to form cumulonimbus clouds - condensation releases heat energy which powers the storm
3) Coriolis effect causes currents of air to rise and cool, descending to leave eye of storm
4) Tropical cyclone enlarges due to heat from oceans
5) Near a landmass, the cyclone decays to become a mere storm
57
Hazards of tropical cyclones
High winds - 119-250 km oer hour or more, trees uprooted by wind and infrastructure is damaged: injury and loss of life
Intense rainfall - Cyclones take in lots of water released as rain, causing flooding that can cause injury and damage to property
Storm surges - Rising sea combines with high winds produced by storm, mass of water forced towards land: these surges erode coastal habitats/defences + flow inland, contaminating farmland + freshwater areas
Coastal flooding - Intense rain + storm surges causes a risk of flooding, which puts people and property at risk, as well as affecting the farming and tourism industries: salt water damages environment
Landslides - Rain saturates soil, soil slides down the slope, affecting settlements at the base of slope and means flooding as this blocks river channels
58
Impacts of tropical cyclones on people
People drown in floodwater
Windspeeds destroy buildings- causing homelessness
Winds + floodwater carries debris which kills or injures people
Floodwater damages cables cutting off electricity supplies
Lack of clean water + sanitation makes it easier for diseases to spread
Crops and livestock killed - shortage of food
Unemployment as businesses are damaged
Damaged roads - aid can't get through
59
Impact of tropical cyclones on the environment
Wooded habitats damaged due to uprooted trees
Storm surges erode beaches/coastal habitats
Saltwater from flooding pollutes freshwater environments
Landslides deposit sediment which kill wildlife
Flooding damages industrial buildings - leaking harmful chemicals
60
Physical vulnerability to tropical cyclones
Areas in the path of tropical cyclones are hit more frequently
Areas of high relief risk heavy rain as this causes landslides
Coastal areas affected more than inland areas
Low relief areas at greater risk from high winds, rain and storm surges
61
Economic vulnerability
Poorer countries depend on agriculture which is badly affected and people don't have insurance to cover costs of repairing damage
Economic impact greater in richer countries as infrastructure costs more
More developed countries have more accurate weather prediction data, better coastal defences and well-established evacuation procedures and disaster response teams. Poorer countries have to wait for international aid.
62
Social vulnerability due to tropical cyclones
Poverty areas more easily damaged/destroyed
Less access in poorer areas to shelter, food and clean water supplies
Areas with a higher or lower age are more vulnerable as older and younger people are more likely to be injured, find it harder to evacuate
63
Preparation
What's done before the event to minimise the disruption to people/environment
64
Response
Events afterwards to help recovery from disruption
65
Preparing for tropical cyclones
Atmospheric pressure - Buoys anchored in tropical ocean areas which send atmospheric pressure
readings, forecasts made on possible storm surges when a cyclone gets closer to land
Satellite tracking and radar -
Large areas of the ocean monitored for the formation of a tropical cyclone, easier to spot on satellite stages once the tropical cyclone has developed an eye, radar provides information from a distance away from the tropical cyclone
Modelling -
Atmospheric pressure data, seawater temperature data and wind speed/direction information is put into modelling programs which help predict the nature of a tropical cyclone
Communicating information-
When a tropical cyclone is forecast, defences are activated in an area and evacuations/emergency services are prepared: information on being prepared for a tropical cyclone
People have time to evacuate and protect their homes/businesses thanks to warning strategies
Governments plan evacuation routes to get people away from storms quickly
The cyclone's magnitude is monitored by measuring the windspeeds
Emergency services train and prepare for disasters
Defences like sea walls built to prevent damage from storm surges: buildings designed to withstand storm surges: less buildings destroyed means fewer people killed/injured/homeless/unemployed
66
Responding to tropical cyclones
Rescue workers search for people trapped in the rubble of collapsed buildings
Food, clean water and medical care provided for the victims of tropical cyclone means fewer people die of injuries, malnutrition or disease
Repair and reconstruction(restoration of drinking water) helps an area recover.
Successful evacuations reduce the number of deaths and injuries
67
Tropical cyclone in a developed country
Hurricane Katrina
Category 3 at Landfall
South East USA
29th August 2005
Coastal habitats like sea turtle breeding beaches are damaged
Flooding damaged oil refineries in Louisiania, causing massive oil spills
More than 1800 people killed
3 million people left without electricity
USA has monitoring system to predict if and where a hurricane hits
The National Hurricane Centre tracks and predicts hurricanes using satellite images.
The NHC issued a hurricane warning on 26th August and continued to update the government on where and when the hurricane would hit
70-80% of New Orleans residents evacuated before the hurricane reached land - meaning less people were killed
Flood defences that were supposed to protect New Orleans failed - meaning 80% of the city was underwater.
68
Tropical cyclone in a developing country
Cyclone Nargis
Category 4 at landfall
2nd May 2008
Irrawaddy Data, Myanmar
The Irrawaddy delta in Myanmar was the hardest hit area, with 14000km2 of land flooded
38000 hectares of mangrove forests were destroyed
450000 houses destroyed - 350000 damaged
People suffered from diseases caused by poor sanitary conditions and contaminated water
Myanmar had no dedicated monitoring centre for tropical cyclones or radar network to predict the height of storm surges and waves.
Warnings didn't reach people in poor communities - people didn't know what to do/where to evacuate to
No early warning system, emergency preparation plans or evacuation plans
Houses made of weak materials(wood)
Aid were refused access to Myanmar until a week after the disaster by the government
69
The asthenosphere
A lubricating layer under the lithosphere due to the movement of tectonic plates- molten/solid rock: upper part of the mantle 80km deep,900-1600C,3.4-4.4g/cm3 density, made of perioditite
70
The mantle
The largest part of the Earth's layers, semi-molten
71
The core
Solid and made up of iron and nickel
72
Continental crust
30-50km, makes up land, thick and less dense, made of granite:
900C, density of 2.7g/cm3
73
Oceanic crust
Under oceans, 6-8km,light but dense as it's made of basalt,
900 degrees, density of 3.3g/cm3
74
Temperature of the centre of the Earth
5500C
75
Convection currents
Heat currents in the molten magma rise and fall due to changing density to create the circular movement of plates as they create drag on the base of the tectonic plates
76
Inner core
Made of iron and nickel
Temperatures of 3700C due to pressure
The centre of the core is very dense
77
Outer core
Less pressure than the inner core
Temperatures in the core(4400-6000C)
Liquid
Iron and nickel
Density of 9.9-12.2g/cm3
78
The Mantle
Molten, source of mantle is Earth's heat which creates convection currents,2900km thick
Silicon-based rocks
1000-3700C
Hotter towards the core and cooler towards the Earth's surface
Largest of Earth's layers
79
The crust
The solid outer layer of the Earth divided into slabs called tectonic plates
80
Convergent plate boundaries
Oceanic plate is forced underneath a continental plate and destroyed to create volcanoes and ocean trenches
When two continental plates meet, the plates collide and are folded to create mountain ranges
e.g. West coast of South America
Tsunamis can form, andesite lava erupts at 900-1000C, Earthquakes magnitude 9.5
Magma rises in plumes through crust: water erupts as steam
Volcanic ash blasted up as pyroclasts
81
Divergent plate boundaries
Two plates move away from each other
Magma rises from gap/rift valleu and cools creating new crust
e.g. Mid Atlantic Ridge, small earthquakes 5-6 on Richter Schale, not explosive or dangerous, erupt basalt lava at 1200C
Basalt magma
Chains of volcanoes form a mid ocean ridge
82
Conservative plate boundaries
Two plates moving sideways past each other in the same direction at different speeds e.g. West Coast of USA
83
Lithosphere
Cool and brittle uppermost layer of Earth, top of mantle/crust
84
Lower mantle
Solide, density of 4.4-5.6g/cm3,
peridotite,1600-4000C
85
Meteorites
Fragments of rock and metal that fall to Earth from space
86
Geothermal heat
Heat from inside the aearth
87
Radioactive decay
Heat produced by elements releasing particles from their nucleus and giving off heat
88
Plumes
Convection cells where heat/magma is brought towards the surface.
89
Magnetosphere
The Earth being surrounded by an invisble magnetic field which protects the Earth from radiation , made by iron in the outer core flowing
90
Pangea
A supercontinent where all the continents were joined together
91
Subduction
Oceanic crust sinking into the mantle at a convergent plate boundary
92
Residual heat
Heat left over from when the Earth formed
93
Pyroclastic flows
Super heated currents of gas, ash and rock emitted by volcanoes
94
Hotspots
Volcanoes form over where a plume of hot magma from the mantle moves towards the crust and breaks through it as a volcano. Hotspots remain stationary, but the crust moves above to create chains of volcanic islands e.g. Hawaii
Oceanic hotspots erupt basaltic lava
Continental hotspots erupt granitic lava
95
Composite volcanoes
E.g. Mount Fuji in Japan
At convergent plate boundaries
Water in crust reacts with magma and creates gas: subducted crust erupts
Erupt thick and sticky andesitic lava due to high silica content, can't flow far so forms a steep sided cone: infreqrent nut violent eruptions from andesitic lava and andesitic lava shatters into pieces to produce lava bombs and pyroclastic flows(hot flows of gas and ash)
Alternate layers of lava and ash
Andesitic lava more viscous(thick and sticky)
96
Shield volcanoes
E.g. Mauna Loa on the Hawaiian islands
Not explosive
At divergent plate boundaries
Eruot basaltic lava which flows quickly to form a gentle sided volcano
Built from lava only
Eruots from fissures
Low silica content, less viscous(more runny and flows long distances before cooling): basaltic lava rarely affects lives
97
Shock waves
Vibrations when plates jerk past each other, represent the earthquake
98
Focus
Point where the Earthquake starts, up to 700km below the Earth's surface
99
Shallow-focus earthquakes
Plates moving at/near the surface, focus 0-70km below the Earth's surface, they displace more water so increase the size of the tsunami
100
Deep-focus earthquakes
Crust moving towards the Earth heating/decomposing
Focus 70-700km below Earth's surface
Less damage than shallow earthquakes as they travel through more rock which reduces power
101
Tsunamis
Enormous waves that form when water gets displaced
102
How do tsunamis form
Underwater earthquakes mean the seabed moves, displacing water. Waves spread from the epicentre of the earthquake(above the focus) and hit the shore without warning
103
Collision plate boundaries
Destructive 9.0 Earthquakes
Landslides
e.g. Himalayas between Indian and Eurasian plates pushing together
Rare volcanoes
When continental plates meet, rock crumples to form fold mountains
104
Volcanoes
Cone-shaped hills/mountains, formed when molten rock from a magma chamber erupts on the surface through a vent in the lithosphere
105
Japan Tohuku Earthquake
In 2011
Magnitude -9
Shallow earthquake makes it more destructive as the focus was 30km deep on a convergent plate boundary
Primary effects -
$235 billion of damage caused by earthquake - costliest disaster in history
Sendai airport closed by tsunami
106
What were the secondary effects of the Sendai, Japan tsunami
15900 people died, 350000 homeless
Businesses disrupted by damage,clearance and rebuilding
107
Long-term planning during the Japan earthquake
Buildings earthquake-proof(steel frames which can sway during Earth's movement, deep foundations for stability and fire-resistant building materials)
Every year Japan has earthquake drills
Advanced warning of earthquake by Japan authorities
In early 2015, all disaster debris was removed
School students and workers participated in annual National Disaster Prevention Day on 1 September
108
Short term relief in Japan
International aid
Power supplies restored
Rescue efforts hampered to disruptions to road and bad weather
109
Causes of Japan Earthquake
The Pacific Plate thrust under the Eurasian plate at the Japan Trench
Tsunami occurred racing out of epicentre at speeds of 800km per hour
110
Haiti Earthquake
Magnitude - 7
Focus - 13km
deep on a conservative plate boundary: very shallow
12 January 2010
Epicentre 25km south west of capital Port au Prince
111
Primary impacts of Haiti Earthquake
316,000 deaths:300,000 people
injured
One prison collapsed:4000 inmates escaped
112
Secondary impacts of Haiti Earthquake
Water supply system destroyed - cholera outbreak killed over 8000 people
Port destroyed - hard to get aid into the area
113
Short-term relief(Haiti)
Emergency aid initially slow due to government buildings destroyed
Food,water, medical supplies and temporary shelters supplied by USA
The UK's Disaster Emergency Committee raised more than £100 million for emergency shelters, medication and bottled water
114
Long-term planning(Haiti)
Unprepared for earthquake
235000 people moved from Port Au Prince to less damaged
cities
200,000 people paid or received food from public work
Cholera epidemic began 10 months after the earthquake killing over 8000 people
115
How much rainfall is there in arid areas?
Less than 250mm a year
116
Why is there low rainfall in arid areas?
Dry air reaching the surface can block moist winds from blowing inland from the sea that would have brought rain
117
Why are countries with a low GDP vulnerable to the impact of natural disasters?
A low GDP per capita makes them less able to afford housing to withstand extreme events
118
GIS cyclone track maps
They show the intensity of wind speed, so measures are put in place to evacuate people
