What is global atmospheric circulation
A world system of winds moving heat from the equator to the poles
What causes global atmospheric circulation
Rotation/tilt of the earth (the amount of light/heat that reaches one part of the earth at certain times
What cells of weather are 30 degrees north and south of the equator
Hadley cells
What happens in a Hadley cell?
The ground is heated which causes Warm air to rise which creates a low pressure zones at the equatior. As the air rises it cools and splits and starts to move towards to poles. When it reaches 30deg north or south the air cools and then sinks towards the ground creating a sub tropical high pressure zones
What weather cell is between 30 degrees north and south of the equator
Ferrel cell
What happens in Ferrel cells
Air on the surface is pulled towards the poles, forming the warm south-westerly winds in the northern hemisphere and north-westerly winds in the southern hemisphere.
These winds pick up moisture as they travel over the oceans. At around 60 degrees N and 60 degrees S, they meet cold air, which has drifted from the poles.
The warmer air from the tropics is lighter than the dense, cold polar air and so it rises as the two air masses meet.
This uplift of air causes low pressure at the surface and the unstable weather conditions that are associated with the mid-latitude depressions. Much of our wet and windy weather in the UK is determined by this.
What weather cell is between 60 and 90 degrees north and south of the equator
Polar cell
What happens in a polar cell
is cooled and sinks towards the ground forming high pressure, this known as the Polar high. It then flows towards the lower latitudes. At about 60 degrees N and S, the cold polar air mixes with warmer tropical air and rises upwards, creating a zone of low pressure called the subpolar low. The boundary between the warm and cold air is called the polar front
Unstable weather
Typoon Hiayan: how many people were killed? Primary effect
6300 (most drowned in storm surge)
Typoon Hiayan: How many people were displaced and how many homes were destroyed. Primary effects
600000 people displaced and 40000 homes destroyed
Typoon Hiayan: how many people were effected in total and how many lost their source of income? Secondary effects
14 million and 6 million lost source of income
Typoon Hiayan: Another secondary effect
Flooding caused landslides which blocked roads intern it cut off aid to remote communities
Typoon Hiayan: immediate responses?
International government and aid agencies responded quickly with food and water
Over 1200 evacuation centres were set up for the homeless
Typhoon Hiayan: long term responses
The UN and countries Including the UK, Australia, Japan and the US donated financial support and supplies to the Philippines
Rebuilding of roads and houses
More cyclone shelters built to accommodate evacuated from coastal areas
Rivers!
What is a drainage basin
is the area of land that is drained by a river and its tributaries
What is the watershed
the area of high land forming the edge of a river basin
What is a confluence
the point at which two rivers meet
How many erosion processes are there on rivers
4
What are the 4 erosion processes on rivers and how do they work
Hydraulic action - This is the sheer power of the water as it smashes against the river banks. Air becomes trapped in the cracks of the river bank and bed, and causes the rock to break apart.
Abrasion - When pebbles grind along the river bank and bed in a sand-papering effect.
Attrition - When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
Solution - When the water dissolves certain types of rocks, eg limestone.
How many types of transportation are there on rivers
What are the 4 types of transportation on river and how to they work
Traction - large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.
Saltation - pebbles are bounced along the river bed, most commonly near the source.
Suspension - lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.
Solution - the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
What happens when a river loses energy
it drops any of the material it has been carrying. This is known as deposition.
Give 3 factors leading to deposition
shallow water
at the end of the river's journey, at the river's mouth
when the volume of the water decreases
What is a long profile
It’s a line representing the river from its source (where it starts) to its mouth (where it meets the sea). It shows how the river changes over its course
What is the rivers load (particles of rock carried by a river) like in the upper course
Large as the rock has not had time to broken down by erosion yet
What is the rivers load (particles of rock carried by a river) like in the lower course
The river's load is fine sediment, as erosion has broken down the rocks.
What is a cross profile
A cross profile shows a cross-section of a river’s channel and valley at a certain point along the river’s course.
A - as the river flows downhill there is an increase in vertical erosion. The channel is shallow and narrow because there is not a lot of water in the channel.
B – as the river flows into the middle course, there is some vertical erosion but more lateral erosion. The channel is wider and deeper as a result.
C - in the lower course there is a lot less erosion, with only some lateral erosion. The channel is at its widest and deepest.
Where are erosional landforms most often found
In the upper course
What are interlocking spurs
interlocking spurs are projecting ridges that extend alternately from the opposite sides of the wall of a V-shaped valley.
Why are interlocking spurs formed
They are formed due to the river avoiding the areas of hard rock which are harder to erode
What type of erosion starts to widen the river
Lateral erosion
Where does deposition occur on a meander
On the inside bank
What causes a river cliff on a meander
Lateral erosion which cause the undercutting of the outside bank to form a river cliff
What is the slip-off slope
A gently sloping bank found on the inside of a river bend due to the slow flowing water depositing material
What is a floodplain
An area of land which is covered in water when a river bursts its banks.
How is a flood plain formed in terms of both erosion and deposition
Erosion removes any interlocking spurs, creating a wide, flat area on either side of the river. During a flood, material being carried by the river is deposited (as the river loses its speed and energy to transport material). Over time, the height of the floodplain increases as material is deposited on either side of the river.
Why are floodplains often agricultural land
Because the flood plain area is very fertile so it is good for growing crops (due to the deposited silt from floods)
Where do levees occur
In the lower course of a river when there is a increase in the volume of water flowing downstream and flooding occurs
Explain how levees occur
Sediment that has been eroded further upstream is transported downstream.
When the river floods, the sediment spreads out across the floodplain.
When a flood occurs, the river loses energy. The largest material is deposited first on the sides of the river banks and smaller material further away.
After many floods, the sediment builds up to increase the height of the river banks, meaning that the channel can carry more water (a greater discharge) and flooding is less likely to occur in the future.
What are levees
They are essentially the embankment of the sides of the river and they can be naturally formed or man made to stop flooding
Where is the river tidal
At the estuary
When the sea retreats the volume of water in the estuary is reduced: what happens when there is less water in the estuary?
The river deposits silt to form mudflats
What are mudflats and what are the important for
They are sheltered coastal areas where silt (mud) is deposited by tides or rivers. They are important habitat for wildlife
One case study example of a river
River tees
Where is the river tees located
North of England
Where is the river tees source located
In the Pennies
Where is the river tees estuary
Near Middlesbrough into the North Sea
When does flooding occur
When a river bursts its banks and overflows onto the surrounding land.
List as many factors as you can that cause flooding
Prolonged rainfall
Heavy rainfall
Relief- more likely to flood on a steep valley than flat. Water will run off into the river more quickly
Geology - permeable rocks allow water to pass through pores and cracks, whereas impermeable rocks do not. If a valley is made up of impermeable rocks, there is a higher chance of flooding as there is an increase in surface run-off.
Vegetation- more vegetation less likely to flood
Urban land use
What does a hydrograph show
How a river responds to a period of rainfall
What is the peak discharge
The maximum amount of water held in the channel
What is the peak rainfall
The maximum amount of rainfall (mm)
What is lag time
The time taken between peak rainfall and peak discharge
What is the rising limb
It shows the increase in discharge on a hydrograph
What is the falling limb
Shows the return in discharge to a normal/base flow on a hydrograph
What is the base flow
The normal discharge of the river
What are the reasons for the lag time being short or long depending on the area
Steep or flat terrain (relief)
Vegetation. How much?
Soil type size of drainage basin
what are hard engineering strategies
They involve building artificial structures which try to control rivers. They tend to be more expensive
What are the advantages of dams and reservoirs
They can be used to produce electricity
Reservoirs and dams can be good for tourism
Very good for controlling the rivers and their floods
What are the disadvantages of dams and rivers
They are very expensive
Habitat flooded from reservoir
River way stopped, so migration routes blocked, very bad for wildlife
what is river straightening and dredging
river straightening speeds up the water so higher volumes can pass through more quickly
River dredging makes the river deeper
What are the advantages of river straightening and dredging
More water can be led in the channel
It reduces the flood risk in that area
What are the disadvantages of river straightening and dredging
Dredging must be done frequently
speeding up the flow of the river increases the flood risk downstream
What do man made river embankments do
They raise the river banks which means the river can hold more water
What are the advantages of embankments
They are cheap with a one off cost
Allows for flood water to be contained in the river
what are the disadvantages of embankments
They look unnatural
And it could cause flooding downstream
What are flood relief channels
Channels created that the floodwater flows into and then is taken either to an area where I can be absorbed, or re-enters the river further down its course
What are the advantages of flood relief channels
It’s removes excess water from the river channel to reduce flooding
What are the disadvantages of a flood relief channel
They are expensive to build
Also if water levels continue to rise it could flood the relief channel
What is an example of river straightening or dredging
River dredging in the Netherlands
What's an example of a river embankment
The river embankment in Moscow
What is a example of a flood relief channel
The organza spillway in Mississippi
when was the Tehran conference
November 1943
What year was yalta conference
February 1945
When was Potsdam conference
July-August 1945
When was the Truman Doctine
March 1947
What is cominform
an organisation made by the ussr which contained ussr satellite states in order for the ussr to easier contain the soviet bloc
When was the Marshall plan and how much money was it.
In 1947/1948
Gave 12.7mil to 13bil already given
When was trizonia created
March 1948
When was the Deutschmark created in west Germany
June 1948
When was the Berlin crisis with the Berlin blockade
1948-49
When was comecon made
1949
After the Marshall plan
When was nato created
April 1949
Included USA, Britain, Canada and France
West Germany joined in 1955
When was the Warsaw Pact formed
1955
After west Germany joined NATO which made USSR worried (big threat)
When was the Hungarian Uprising
1956
When did Stalin die and when did krushchev leader
1953
How many tanks and troops were sent into Hungry by USSR on there second invasion
60000 troops
1000 tanks
How many people were killed in the Hungarian uprising and how many refugees were there
20000 killed
200000 refugees
When was the second (bigger) Berlin Crisis
1958-1963
When was the Berlin Wall built
1961
How many annual refugees went from east to west Germany
150000-200000
When was the Berlin Ultimatum
November 1958
When were the first two summit meetings between the superpowers to try and improve relations
Geneva
Camp David
Geneva: may 1959
Camp David: September 1959
Both improved relations
USSR even withdrew the Berlin Ultimatum at Camp David
When and what happened and Paris (3rd meeting)
May 1960
U2 spy plane shot down over USSR just before summit
Krushchev walks out of summit
Clearly extremely damaged relations
When was and what happened at Vienna summit
June 1961
New President of Kennedy
Khrushchev tried to take advantage of his inexperience and renewed the Berlin Ultimatum.
Kennedy refused to make concessions
More bad relations
When was the bay of pigs incident
April 1961
When was the Cuban missile crisis
October 1962
When was Salt1
1972
When was the Helsinki accords
1975
How many soviet troops were killed in Afghanistan
15000
How much did the war against the Mujahideen cost the soviets per year
8bil per year
When did Reagan replace Carter as president
1980
When was the Reagan Doctrine
1985
Said he would support anti communist governments and groups fighting against communism
What is a closed system
There is low energy into and out of the system
What is an open system
This receives inputs transfers and outputs of energy and matter across boundaries
Last changed19 days ago
