Geography Revision for Standard Grade Weather Depressions are low pressure systems. These affect the UK for much of the year. These bring cloud, rain, wind and generally unsettled conditions. Depressions – how are they formed? Depressions form where warm air meets cold air The boundary between the two air masses is called a front Along a front there will usually be thick cloud and heavy rain A Depression Warm Front Cold Front Passage of a depression Anticyclones – high pressure High pressure synoptic chart The word high is written in the middle of the high pressure area The isobars are widely spaced The value of the isobars get higher towards the centre of the anticyclone Anticyclone weather - Summer Dry and hot days with little or no cloud. Early morning dew and mist. Nights are cool due to lack of cloud during the day. Anticyclone weather - Winter Fog that may last all day. Mostly clear skies. Frost in the mornings. Freezing nights. Dry. Rivers – The upper course V-shaped valleys. (erosion) Waterfalls. (erosion) Fast flowing water. The middle and lower course Meanders (erosion and deposition). Ox bow lakes (erosion and deposition). Floodplain. Embankments or levees. River processes - definitions EROSION This is the wearing away of land. Most erosion occurs when a river is in flood. This is when it flows fastest and can carry huge amounts of material. There are four main types of erosion Types of erosion Attrition - Material is moved along the river bed, collides with other material and breaks up into smaller pieces. Corrasion – is caused by fine material rubbing against the river back. The action is rather like sandpaper. Corrosion – is a form of chemical erosion. The backs and bed of the river are dissolved by acids in the water Types of erosion Hydraulic Action – is the force of water hitting the banks of the river. It wears them away and causes them to collapse. Deposition This is the laying down or dumping of material. It happens when a river slows and loses energy. This may be during a dry spell, on the inside of a river bend, or when the river reaches the sea. Transportation This is the movement of eroded material. The material includes sand particles, pebbles and even large boulders. There are four ways that material can be transported. Types of transportation Traction – large rocks and boulders are rolled along the bed of a river. Saltation – smaller stones are bounced along the bed of a river in a leap-frogging movement. Suspension – fine material is light enough to be carried by the river. The material may discolour the water. Solution – some minerals dissolve in the water. These are always present in the river. Glaciation – features of erosion U shaped valley. Corrie. Arete. Pyramidal peak. Corrie Pyramidal Peak U-shaped valley Glaciation – features of deposition Moraine (terminal, lateral, medial) Drumlin. Esker. Kettle hole. Terminal Moraine. Outwash Plain. Erratic. Kames. Deposition Land Use Think of the different ways tourists and locals in an area can use a glaciated valley. How do their activities differ between an eroded glacial landscape and a landscape formed by deposition? How might these activities cause conflict? Settlement – Function (what a settlement does or provides) Old or New Industrial Towns. Market Towns. Ports. Tourist Resort. Sphere of influence The distance or range that people are prepared to travel to buy goods or use services The shops and services of a hamlet or small village are mostly used by local people. The Sphere of influence of these places is small. A large town serves the needs of its local inhabitants but also has sufficient shops and services to attract people from far away. The sphere of influence is therefore large. Patterns and types Land use models - Burgess What are the features of… CBD. Inner City. Suburbs. Countryside. Industry - types Primary. Secondary. Tertiary. Industry – Factors affecting location Labour Transport Flat land Raw materials Power supply Near to market Government policies Capital Environment Old Industry Coal mining, steel works, heavy industries. Old industries declined and many people became unemployed. Workforce taken over by machinery. Causes problems in industrial areas – Social, Economic and Environmental problems. Mostly located in inner city areas. Light industries Mostly electronics. Located on outskirts of towns (out with suburbs). Industrial estates. Located mostly at the edges of towns. Close to fast communications, especially main roads. On cheap flat land. Where there is room to expand. Close to workers. Climate Regions – Mediterranean Climate Very hot summers, temps can be over 30 C. Warm winters with temps around 10 C. Total rainfall is about 300 – 500 mm. Wet in winter with many days of drizzle. Very little rain in the summer, can cause drought. Occasional heavy thunderstorms in summer. o o Problems Drought. Fires. Tourist related problems – pollution, noise. Oil spills. Chemicals used in farming. Equatorial Rainforests Equatorial Rainforests Shifting Cultivation is practised by tribes living in the rainforest. Firstly, the Amerindians cut down a small area of the forest to make a clearing. They cut down the trees and burn the stumps. This is called ‘ Slash and Burn’. The ash from the burnt tree stumps is then spread over the soil. The ash makes the soil very fertile and good for growing crops. The tree trunks are then used to make their houses, called malocas. Deforestation Reasons for destroying the rainforest include: Cattle ranching New Roads Hydro-electricity New towns and settlement Logging – timber Mining Hot Deserts Problems in the desert. The biggest problem to the people living near to the deserts is desertification. Desertification is the gradual change of land into desert. The Sahel is one of the worst areas affected by this. The Sahel is the belt of land to the south of the Sahara desert. In the Sahel, the desert is advancing in places by up to 6km a year. Desertification More More People Animals More Firewood More Crops Natural Hazards Overgrazing Deforestation BARE SOILS Over cultivation Insects Eat crops Drought Vegetation dies Climate change Less rain DESERTIFICATION The land provides Less food Causes of Desertification Climatic Change Decrease in rainfall since 1960, perhaps due to Global warming Over grazing Population Growth Too many animals for Farmers have to grow the grass available. No more crops to feed the vegetation = soil growing population. erosion Trees removed for fuel Tundra Tundra Climate Tundra areas have temperatures below zero for around 6 – 8 months of the year. In the summer months the temperature creeps just above zero. In the winter, the sun doesn’t rise above the horizon and the tundra is dark all day and night. Strong winds mean there is a high wind chill factor – making it seem even colder. Rainfall in the tundra is very low, less than 250mm per year. It is sometimes called the cold desert. Most precipitation falls in the winter as snow. Permafrost In Tundra areas the soil remains frozen all year round and only the very top layer will thaw out in the summer months. The layer which thaws out is called Muskeg. Underneath this top layer, the soil is permanently frozen. This layer is called Permafrost. This makes it difficult to build in the tundra and most buildings have to be built on stilts. Oil in the Tundra Oil tankers were not much use for transporting oil because the Arctic Ocean is frozen for much of the year. Instead, a 1242km (about 800 miles) pipeline was built from Prudhoe bay in the North to Valdez in the South. This route faced huge physical and environmental problems. Why could the pipes to carry the oil not be placed underground. Population Population Distribution. Population Density. What is the Demographic Transition Model. This is a model which shows the changes in birth rate and death rate. It also shows how the BR and DR can affect population growth. The model shows that population growth can be divided into 4 stages. All countries fit into one of the stages of the model. Demographic Transition Birth Rate, Death Rate and Natural Increase. The Population Structure of a country Population Pyramids Show : The population of a country divided into five year age groups. The percentage of people in each age group. The percentage of males and females in each age group. Changes in BR, DR, Life expectancy and infant mortality. The proportion of elderly and young people who are dependent on the rest of the population. The effects of people migrating in and out of the country. Population Pyramid - UK Population Pyramid - Chad What is migration ? Migration is the movement of people from one place to another to live or work. This can be short distance ( e.g. to the next town) or it may be longer distance (e.g. moving to another country). Some migrations can be temporary and people will return to their homes. Or it can be a permanent move. Push and Pull factors Push Factors : These are things about the area that people live in that make them want to move somewhere else. These are negative factors. Pull Factors : These are things about the new area that people are moving to that make them want to live there. These are positive factors. Farming Arable farming Livestock farming Mixed farming Hill sheep farming Market Gardening Farming Changes Farm size. Machinery. Removal of Hedgerows. Use of Chemicals. Crops Grown. Jobs Available. Wildlife. Farm workers cottages. Natural Environment. Land Use (recreation) Common Agricultural Policy (CAP) This policy was introduced in order to help farmers provide an efficient and reliable way of producing food within the EU. Farmers are given a guaranteed price for their produce – subsidies. This allowed farmers to run their farms more successfully and invest in new equipment. This led to problems of over production.