Flashcards in Theme 2 Deck (107):
What're the 5 main reasons for climate varying in the UK?
Distance from the sea
What does a synoptic chart show?
Atmospheric pressure conditions
What is atmospheric pressure measured in and what is it shown as on a synoptic chart?
As you go towards the centre of the circular shape on a synoptic chart showing low pressure will the numbers decrease or increase?
As you go towards the centre of the circular shape on a synoptic chart showing high pressure will the numbers decrease or increase?
Draw the symbols for a warm front, cold front and occluded front?
Warm- line with red semi circles
Cold- line with blue triangles
Occluded- line with both red semi circles and blue triangles
Name the three types of rainfall
Relief, convectional and frontal
Describe relief rainfall
Warm wet winds reach a mountain barrier and have to rise over it.
The air cools and condenses forming clouds and precipitation starts.
The drier air starts to descend.
This drier area is know as the rain shadow.
Describe convectional rainfall
Sun heats the ground and warm air rises
As it rises it cools and cumulonimbus clouds are formed by strong thermal up currents which produce low pressure
Describe frontal rainfall
A low is formed where warm and cold air meet which causes condensation and frontal rain
Describe how a depression forms
Warm moist air is less dense than cold dry air and therefore rises above when they meet
Rising air causes low pressure at the earths surface so winds blow into the depression in a spiral
What weather conditions do anticyclones bring?
Winter: clear bright skies, low night temperatures
Summer: dry hot weather
Name a period of extreme weather
European heatwave 2003
What are the causes, effects and responses of the European heat wave?
Causes: anticyclone/area of high pressure over Europe
2,000 heat related deaths, road surfaces melted, increased sales in fans, ice creams and tourism, melting glaciers in the alps, forest fires, 10% of Portugals forests destroyed
Responses: advances warning, hose pipe bans and France asked EU for money
Name some impacts of extreme weather
Floods damage houses and businesses, water use restricted in droughts, droughts cause crop failures, flooding causes drowning, heat exhaustion, floods block transport systems
Increased rainfall increases water supplies and higher crop yields, warmer climate means farmers can grow crops which they could before
How is a hurricane formed?
Over sea water, more than 27 degrees
Warm moist air rises and condenses releasing huge amounts of energy
They move west because of easterly winds near the equator
They spin anticlockwise and the centre if the storm is called the eye
Name a case study for hurricanes
Hurricane Katrina, New Orleans, USA, August 23rd 2005, category 4
What were the causes of hurricane Katrina?
29-33 degrees over the Gulf of Mexico
Extreme low pressure as a result of warm updrafts
Development of cumulonimbus clouds leading to high rainfall
What were the effects of hurricane Katrina?
1,300 death till-drowning/exposure
Flood damage (80% of New Orleans under water)
Fires form gas pipes, pylons and people using candles
What were the responses to hurricane Katrina?
Evacuation if thousands before+after
Ambulances and helicopters to help
Army and aid agencies supply food and clothes
Police to prevent looting
Areas made to shelters (Louisiana super dome)
Flood water pumped out
Define a producer
An organism that uses sunlight energy to produce food
Define a consumer
An organism that gets its energy by eat other organisms
Define a decomposer
An organism that gets its energy by breaking down dead material
Describe a temperate deciduous forest
Found mainly in Europe
Have four distinct seasons
There's rainfall all year round
Soil is feel and fertile because of a thick layer of leaf fall
Undergrowth-shrub layer-tree layer
Describe a tropical rainforest
The Amazon, Central Africa, SE Asia
Hot wet climate
Soil isn't that fertile as heavy rain washes nutrients away
Shrub layer- under canopy- canopy-emergents
What sort of climate so tropical rainforests grow in?
What do large buttress roots do?
Support the trees
What're the 5 main causes of deforestation?
What're the economic and political impacts of deforestation?
Makes lots if money
Pressure on governments to stop deforestation
What're the environmental and social impacts of deforestation?
Livelihoods ruined when animals and plants that they rely on are destroyed
Native tribes forced to move
Conflict over land use
Give an example of a tropical rainforest facing deforestation
What're the responses to deforestation?
Sustainable development e.g. Ecotourism
Protect certain areas
Replant action scheme
How can tropical rainforests be sustainably developed?
Reducing demand for hardwood
Reducing debt in poor countries with tropical rainforests
Name an area suffering from desertification
Sahel region, Africa
Describe the reasons that desertification
Population growth->more fuel, food and housing needed->tress are cut down and grassland is over grazed........
Climate change->less rain and more evapotranspiration.............
soil become bare->soil is eroded by wind and water-> land becomes infertile->no plants grow-> land becomes desert
What're the solutions to desertification?
What're the impacts of desertification?
Lack of wood
Reduced quality of life
What is the hydrological cycle?
Continuous movement if a constant amount of water between sea, land and atmosphere
How does water go through the hydrological cycle?
Evaporation of sea water forms clouds
Rainwater sinks into the ground (vertical transfer)
Water moves back to the sea (horizontal transfer)
Some water is also stored on the surface and eventually returns to the atmosphere
What is the course of the river long profile like?
Upper: steep gradient, narrow and shallow sides, vertical erosion
Lower: gentle gradient, almost flat sides, very wide and deep, lateral erosion
What is a drainage basin?
A land area drained by a river
What is the catchment area?
The land area from which a five and it's tributaries collect the water passing from the soil and rock
What is a watershed?
High ground separating two neighbouring drainage areas
Name 3 inputs of a drainage basin?
Name 3 processes in a drainage basin
Name 2 outputs in a drainage basin
What is a source of a river?
Where a river starts usually in an upland area
What is a tributary?
A branch of the main river
What is a confluence?
The point where two rivers join
What is the mouth of a river?
Where the river flows into the sea
What is an estuary of a river?
The mouth is low enough to let the sea enter at high tide which causes deposition
7 uses of drainage basins
Farming (fertile soil)
Water (consumption and HEP)
Transport (moving goods)
Settlement (locating by water for water use)
Afforestation (fertile soil)
Large pieces of bed load wear away the riverbed and banks
Sediment particles hit into each other and break apart, becoming smaller and more rounded
Define hydraulic action
Force of the water wears away at softer rocks and can weaken harder rocks with faults
Chemicals in the water dissolve the rock
Large particles are pushed across the river bed
Pebble sized particles are bounced along the river bed
Small particles are carried along by the water
Soluble materials dissolved in the water are carried along
When a river drops eroded material
E.g. When a river slows down, amount of eroded material increase or the water is shallower
What is a meander?
Large bends in a river, found in the middle and lower courses
What're the features of a meander?
The current is faster on the outside of the bend because the channel is deeper, more erosion them takes place forming river cliffs
Current is slower on inside of the bend because the channel is shallower forming slip off slopes
Describe how an ox bow lake is formed
1) Erosion causes the outside bends to get closer until there's a small bit of land left
2) The river breaks through this land during a flood and the river flows along this new route
3) Deposition eventually cuts off the meander
What is a flood plain?
A wide valley floor which occasionally gets flooded
Flood plains are built up because material is deposited when the water slows down over it in a flood
Meanders move across flood plains making it wider
What is a levee?
A natural embankment created as deposited material builds up
How is a waterfall and gorge formed? (Upper course of river)
Softer rock is eroded more than hard rock, a steep drop is eventually created
Hard rock is undercut, becomes unsupported and collapses
A plunge pool is created as this material is swirled around
The waterfall will retreat, leaving a steep sided gorge behind
How can contour line show you the direction of the river?
Number marked in contour lines will tell you the steepness- rivers flow downhill
What is river discharge?
The volume of water flowing in a river per second (measured in cumecs)
Define lag time
The delay between peak rainfall and peak discharge
What does a hydrograph show?
River discharge and rainfall
What is base flow on a hydrograph?
Normal discharge of a river
What 6 factors affect river discharge?
Temperature (hard ground increases run off)
Amount and type of rainfall
Previous weather conditions (saturated soil increases run off)
Land use (impermeable surfaces increase run off)
Relief (height of the land increases run off)
Rock type (impermeable rock increases run off)
Name two human factors which contribute to rivers flooding
What is hard engineering?
Reducing the risk of flooding
What is soft engineering?
Reducing the effects of flooding
Give an example of hard engineering
Dams and reservoirs
Give a few examples of soft engineering
Flood warnings, floodplain zoning
What were the causes for Boscastle flooding?
Peak discharge of 100 cumecs
Peak rainfall 120mm in 1hour
What were the effects of Boscastle flooding?
Tourists cut their holidays short
What were the responses to the Boscastle flood?
7 helicopters rescues 150 people
Water pumped out of flooded houses
Houses and roads repaired
Facts for Boscastle
Cornwall, SE England
River Jordan and River Valency
What is freeze thaw weathering?
When temp alternates above and below 0 degrees
Water gets into rocks with cracks
When water freezes it expands which puts pressure on the rock
When water thaws it contracts, releasing the pressure
This process widens the crack and causes the rock to break up
Describe a destructive wave
Waves with a high frequency
High ands steep
More powerful backwash than awash resulting in erosion of the coastline
What is mass movement?
Shifting of rocks and loose material down a slope
Occurs when force of gravity is greater than force supporting it
What is the difference between slides and slumps?
Slides- material shifts in a straight line
Slumps- material shift with a rotation
How are wave cut platforms formed?
Waves erode cliff to form a wave cut notch, the rock above becomes unstable and collapses, this is washed away and the process happens again, as the cliff retreats a wave cut platform is left
What is the reason for the formation of headlands and bays?
How is a stack formed?
Headlands are usually made of resistant rocks with cracks, waves enlarge the cracks by erosion, this eventually forms a cave, this cave is deepened by erosion until it breaks through to form a arch, unsupported material collapses, leaving a stack
How is material transported along the coast?
Describe the process of Longshore drift
Waves follow the direction of the prevailing (most common) wind and hit the coast
The swash carried the material up the beach and the backwash carries it down the beach to the sea at right angles
What is a constructive wave?
Builds up the coastline as it deposits material
Low and long
Swash is more powerful than backwash
How is a spit formed?
Longshore drift transports material past a sharp bend in the coast
The sheltered area behind is protected by waves and can allow a mud flat or salt marsh to form
What is a bar?
When a spots joins two headlands together, a lagoon can then form behind the bar
Name a fast eroding coastline in Europe
Holderness in East Yorkshire stretching from Flamborough Head to Spurn Head
What are the reasons for erosion at Holderness?
Easily eroded rock-boulder clay
Naturally narrow beaches
People-coastal defences built at Mappleton affect other places
Powerful waves as have a long fetch
What're the impacts of erosion at Holderness?
Homes at risk
Property prices falling
Businesses at risk
Gas terminal at Easington at risk which supplies 25% of Britains gas
Lagoons at risk of being connected to the sea and will be destroyed
Name some methods of hard engineering to prevent coastal erosion
Name some methods of soft engineering to manage coastal erosion
What are they?
Concrete walls to reflect waves
❌Expensive and must be maintained
What are they?
Boulders piled up
✅Fairly cheap, absorb wave energy reducing erosion and flooding
❌Boulders can be moved so need to be replaced
What are they?
Wooden fences built at right angles to trap material from Longshore drift
✅Create wider beaches, fairly cheap, prevents flooding and erosion
❌Put areas further down the coast at risk
What are they?
Material added to beaches
✅Creates wider beaches
❌Expensive and must be repeated
What are they?
Restoring sand dunes
✅Prevents flooding and erosion
❌Expensive and limited to a small internet
What are they?
Removing an existing defence and allowing the land behind to flood
✅Land will become marshland creating new habitats, cheap
❌Disagreements over land being flooded e.g. Farmland
How is Holderness protected from erosion?