Weather and Climate

Related Case Study:

Hurricane Katrina

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Climate and Anticyclones

  • High air pressure > Air is sinking > Clouds can't form > Dry
  • Low air pressure > Air is rising > Clouds can form > Wet


  • A slow moving weather system caused by high pressure of 1016mb.
  • Low wind speeds (shown on a weather map by the isobars being spread out).
  • In summer it brings high temperatures and the opposite for winter.
  • Drought and water shortages.
  • More forest fires in summer as vegetation dries out.
  • There may be a hose pipe ban.
  • There may be water rationing.
  • In the winter, local councils will grit the roads if it will be below 0'C.
  • Those involved in outdoor activities will gain.
  • Tourist related businesses will gain in summer.
  • The elderly and those with health problems are more at risk in extreme hot or cold weather.
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  • Warm and cold air meet at the front and then the warm air forces its way into the cold air.
  • Two lots of rain.
  • A lot of cloud on and near the fronts.
  • High wind speeds.
  • Flooding if the depression brings a lot of rain.
  • In winter, it may bring snow if the temperatures are low enough.
  • Structural damages due to high wind speeds.
  • The Environment Agency issues flood warnings.
  • Schools may be forced to close.
  • Football matches may have to abandon matches.
  • The Environment Agency is responsible for monitering rivers.
  • Commuters may have to change their journey plans.
  • Parents may have to arrange child care at short notice.
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Tropical Storms e.g. Hurricanes

  • Very low pressure weather systems.
  • Strong winds.
  • Heavy rainfall.

Tropical depressions have winds less than 38mph, Tropical storms have winds between 39-73mph and hurricanes have winds over 74mph.

  • Recorded on the Saffir - Simpson scale.

How do hurricanes form?:

  • Low pressure area.
  • Warm water.
  • Coriolis Force.
  • The atmosphere.
  • The wind.
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Hurricane Katrina


  • It was formed over the Bahamas on 23rd August 2005.
  • Crossed Florida as a small hurricane.
  • Strengthened rapidly over the Gulf of Mexico.
  • Second landfall on the 29th August 2005 in Louisiana.
  • The storm broke up on the 31st August 2005.


  • The city of New Orleans, in Louisiana.
  • Alabama was also affected.


  • Sea temperature of 27'C.
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Hurricane Katrina


  • 1800 people died.
  • The costs are estimates at $75 billion.
  • 1 million people were evacuated from New Orleans.
  • 80% of New Orleans were submerged under 6ft of water.
  • 9000 people took shelter in the Superdome.
  • The government were criticised for not helping the people of New Orleans quickly enough.
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Related Case Study:

Amazon Rainforest / Bramcote Woods

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Key Services and Management

  • Maintaining a steady supply of clean water to rivers.
  • Preventing soil erosion.
  • Reducing the risk of river floods.
  • Providing natural meterials such as timber for building, or plants for medicine use.
  • Providing food stuffs such as honey, fruit and nuts.

How can ecosystems be managed sustainably?

  • Allowing access to parts of an ecosystem and protecting the rest.
  • Encouraging responsible use of an ecosystem - Sign posts, Bins, Fences, Paths.
  • Encouraging activities that use the wood in a non-harmful way.
  • Replanting trees that are removed.
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Human Impacts in the Wood - Bramcote

Different Groups of People:

The wood is managed by Broxtowe Council. People who use the wood are:

  • People walking their dog.
  • Families.
  • People keeping fit.
  • Mountain bikers.
  • Local school children taking a short cut.
  • Horse riders.


  • Soil erosion from people walking and mountain biking.
  • Litter and vandalism.


  • Tree planting at the top of the hill.
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Related Case Study:


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Location and Causes

 The Sahel is located in the southern region of the Sahara Desert, Africa.

Causes of desertification:

  • An increase in population --> Deforestation --> Overcultivation --> Loose top soil blown away or eroded by rainfall ..
  • An increase in population --> An increase in cattle --> Overgrazing --> Less vegetation --> Loose top soil blown away or eroded by rainfall ..

Human Causes and Solutions:

  • Deforestation = Afforestation.
  • Overcultivation = Educate the farmers to use the land in a productuve way.
  • Overgrazing = Plant acacia trees for use as food for the animals.
  • Over use of fertilisers = Use genetically modified crops.
  • Lack of irrigation = Build terraces on the land to help conserve water.
  • Poverty/Civil War = Build stone lines across fields.
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Causes and Groups of People

Physical Causes and Solutions:

  • Climate change and drought = Irrigation schemes or dams.
  • Variations in seasonal rainfall = Storing water during rainy seasons and plant more drought tolerant crops (GMC)
  • High pressure systems = None

Groups of People:

  • The people who live in the Sahel region struggle to survive. Many face starvation or malnutrition.
  • The United Narions has a convention to tackle the problems of desertification.
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River Processes and Landforms

Related Case Study:

River Trent and Flood Defences in Duffield

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Related Case Study:

The Dorset Coast

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Location and Landforms

 Dorset is a county in South West England on the English Channel coast.

  • Old Harry is an example of a stack.
  • Durdle Door is an example of an arch.
  • Swanage Bay is an example of a bay between two headlands.
  • Kimmeridge is an example of a wave-cut platform.

Headlands and Bays - Erosional Landforms:

  • This type of coastline is called discordant.
  • This coastline is eroded by abrasion and hydraulic action.
  • Soft rock is eroded quicker to create bays.
  • Swanage Bay is made from clays and sands.
  • Hard rock is left sticking into the sea as headlands.
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Wave-cut Platforms and Cliff Recession - Erosional Landforms:

  • Weather weakens the top of the cliff.
  • The sea attacks the base of the cliff forming a wave-cut notch.
  • The notch increases in size causing the cliff to collapse.
  • The notch forms between the wave height at high and low tide.
  • The backwash carries the rubble towards the sea forming a wave-cut platform.
  • The process repeats and the cliff continues to recede.

Caves, Arches and Stacks - Erosional Landforms:

  • These features are formed on cliffs or headlands that are made of hard rock.
  • This hard rock is eroded by abrasion and hydraulic action.
  • Old Harry is made from chalk.
  • Durdle door is made from limestone.

Depositional Landforms:

  • Sandbanks is an example of a spit.
  • Chesil Beach is an example of a tombolo.
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Landforms and Management

Spits, Bars and Tombolos - Depositional Landforms:

  • Spits are created by deposition
  • They are formed where the prevailing wind blows at an angle to the coastline.
  • A tombolo is a spit that has joined onto an island.

Why do coastal processes need to be managed?

  • Increasing development of coastal areas including urban areas means there are more people at risk from coastal flooding.
  • This risk is likely to increase in the future as climate change causes rising sea levels and an increase in the number of coastal storms.
  • The value of coasts for leisure and recreation.
  • Increased economic/transportation/industrial value in industries like oil refineries and ports.
  • Increased environmental/nature conservation value of coastal wetlands
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How are coastlines managed?

  • Hold the existing defence line - To maintain or increase the level of protection provided by defences in their present location.
  • Advance the existing defence line - Building new defences on the seaward side of the existing defence line to reclaim land.
  • Managed realignment - Allowing the shoreline to position to move backwards (or forwards) in a controlled way.
  • Do nothing - A decision to not invest in providing new or maintaining existing defences.

Management Methods:

  • Gabions - Hard engineering
  • Sea walls - Hard engineering
  • Rip rap - Hard engineering
  • Groynes - Hard engineering
  • Beach replenishment
  • Revetments - Hard engineering
  • Breakwaters - Hard engineering
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Swanage Bay, Holderness Coast and Arguments

Swanage Bay:

  • Sea wall,
  • Groynes and,
  • Beach replenishment.

 They have a hold the line policy.

Holderness Coast:

  • Concrete sea walls,
  • Wooden groynes and,
  • Rock armour.

Arguments For and Against Sea Defences:

  • People have lived in these areas for generations.
  • Houses, schools, roads, hotels, agricultural land will be lost.
  • The cost is expensive.
  • The land is not that valuable in some places.
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Upper Course of a River

V-Shaped Valleys - Erosional Landform:

  • Vertical Erosion - Results in a number of distinctive landforms including the steep sloping v-shaped valley through which the river flows in its upper course.
  • Over time the sides of this valley are weakened by weathering processes.
  • As the river flows through the valley it is forced to swing from side to side around more resistant rock outcrops (spurs).

Waterfalls - Erosional Landform:

  • Waterfalls often form where hard rock lies over the top of a softer rock.
  • The water drops over the edge and swirls around in the plunge pool which erodes the soft rock.
  • The soft rock is eroded back.
  • The hard rock is left to overhand.
  • The position of the waterfall moves backwards (retreats).
  • Over a long time this will carve out a deep sided velley called a gorge.
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Middle Course of a River

Meanders - Erosional and Depositional Landforms:

  • In the middle course, the river has more energy and a high volume of water.
  • The gradient here is gentle and the lateral (sideways) erosion has widened the river channel.
  • Outside of the bend = The force of the water erodes and undercuts the river bank on the outside of the bend where water flow has most energy due to decreased friction.
  • Inside of the bend = The river's flow is slower so it has less energy. This means material is deposited, as there is more friction.
  • On the outside bend, a steep bank called a river cliff is formed.
  • On the inside, the build-up of deposited material creates a slip off slope.
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Lower Course of a River and Flooding

Floodplains and Levees - Depositional Landforms:

  • Levees are the higher banks that develop at the edge of the river.

River Flooding:

 A flood is a period of high river discharge or, alone the coast, an extremely high tide.

 A hydrograph is a graph to show changes in discharge of a river over a period of time.

  • Urban areas - Increases the risk of flooding due to being covered in impermeable surfaces.
  • Deforestation - Increases flood risk because trees intercept some of the rain.
  • Intensity of the rainfall - A heavy rainstorm will put a lot of water onto the land in a short period of time.
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River Trent Floods of December 2012


  • Farmers have removed trees in Derbyshire.
  • High rainfall for many weeks - In Rolleston, they recieved 75mm in 24hrs.
  • Impermeable surfaces in Derby and Burton on Trent.


  • Notts County football match was cancelled.
  • Trains were cancelled between Crewe and Derby.
  • Toot Hill school in Bingham was closed.
  • Fire crews were called out to rescue stranded animals.


  • Dam Construction.
  • River Engineering.
  • Dredging.
  • Afforestation.
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Interest Groups

  • Governments and developers often favour large hard enginerring options, such as dam building. Building a dam and a reservoir can generate income. Profits can be made from generating electricity or leisure revenue.
  • Environemtal groups and local residents often prefer softer options, such as planting trees. Soft options cause little damage to the environment and do not involve the resettlement of communities.
  • Effective flood management strategies should be economically, environmentally and socially sustainable. Sustainable strategies allow management without compromising the needs of future generations.
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