Higher Geography Atmosphere

Higher Geography Atmosphere

INTRODUCTION Skin cancers Acid rain Global warming Greenhouse gases
ATMOSPHERE INTRODUCTION Skin cancers Acid rain Global warming Atmosphere in the news Greenhouse gases Hole in the ozone layer CFC’s Climate change Although considered a difficult topic, this is the most up-to-date of the basic units!

In this unit we will be covering the following topics:
Topic 1: Global Insolation Topic 2: Atmospheric Circulation Topic 3: Oceanic Circulation Topic 4: Air Masses Topic 5: Climatic Change

Today we are going to find out:
What the atmosphere is and why it is important. What global insolation and the heat budget are. Why variations in insolation occur.

What is the atmosphere? Originally formed as the earth cooled, the atmosphere is a blanket of gases which contains solid material, such as volcanic dust and blown soils, and is attached to earth by the force of gravity.

This atmosphere is a mixture of oxygen (21%), nitrogen (78%), carbon dioxide (0.037%) and other gases such as hydrogen, helium, argon, neon, krypton, xenon and ozone. It also contains water vapour. These gases are densest at the Earth's surface and get less dense with increasing height. Around 90% of the atmosphere by weight lies in the lowest 15 km (9 miles) above the surface and it is only a very thin skin of air that keeps all life on Earth alive.

There are five main layers in the atmosphere.
1) The troposphere contains approximately 75% of the atmosphere's mass, and has an average depth of about 16 km. The troposphere is is where weather systems develop.

2) The stratosphere 16-50km is dry with rising temperatures
2) The stratosphere 16-50km is dry with rising temperatures. It contains large amounts of ozone gas which protects life on earth by filtering out most of the Sun’s harmful rays.

3) Many rock fragments from space burn up in the mesosphere km (middle sphere). As it lies between the maximum altitude for aircraft and the minimum altitude for orbital spacecraft, this is the most poorly understood part of the atmosphere.

4) The thermosphere is directly above the mesosphere
4) The thermosphere is directly above the mesosphere. Within this layer, ultraviolet radiation causes ionization. The thermosphere, named from the Greek (thermos) for heat, begins about 80 km above the earth and can experience temperatures of 2,500°C. .

5) The upper limit of our atmosphere is the exosphere
5) The upper limit of our atmosphere is the exosphere. The main gases within the exosphere are the lightest gases, mainly hydrogen, with some helium, carbon dioxide, and atomic oxygen.

Topic 1: Global Insolation
Insolation: incoming solar energy Less than half the incoming solar energy actually penetrates to the surface of the earth. The rest is lost in a variety of ways.

The Heat Budget Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer, or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth’s heat budget.

Atmosphere As the sun’s rays pass through the atmosphere, some are reflected, some absorbed and some pass through to reach the earth’s surface.

SOLAR INSOLATION ATMOSPHERE 100% 25% 23% 52% 6% 46%
reflected by clouds and dust, water vapour and other gases in the atmosphere 100% 25% absorbed by clouds and dust, water vapour and other gases in the atmosphere 23% 52% reflected by surface 6% absorbed by surface 46% earth

COPY AND MEMORISE THIS DIAGRAM!
The Heat Budget (p1) COPY AND MEMORISE THIS DIAGRAM!

The Heat Budget Incoming insolation = 100% 46% absorbed at surface
6% reflected by surface 19% absorbed by atmosphere 8% reflected by atmosphere 4% absorbed by clouds 17% reflected by clouds

Variations in Insolation
Because the earth is a sphere, there are variations in the amounts of insolation received in different places. Both bands of solar radiation are of the same strength. The band near the north pole though has to heat a large area (D-E) due the curve of the earth. The band at the equator can concentrate its heat in a smaller area A-B AGAIN, COPY AND MEMORISE THIS DIAGRAM!

Latitudinal Variations in insolation

Radiation Budget We can also compare energy received by the earth (insolation) with energy lost by radiation (terrestrial radiation). Insolation: solar energy received by the earth. Terrestrial radiation: solar energy lost by radiation. At the equator: insolation is greater than terrestrial radiation (due to darker forest material and higher land concentration), leading to a surplus in energy. At the polar zones, insolation is weak and terrestrial radiation is high (due to lighter light-reflecting snow + lower land concentration), leading to an energy deficit.

Latitudinal Variations in insolation Past Paper Q. (2002)
Describe the latitudinal variation of the earth’s energy balance shown in the diagram (4 marks) Hints: what is max/min terrestrial radiation? max/min insolation? Where is there a balance between the two? Total surpluses/deficits?

Seasonal Insolation Not only does insolation vary with latitude, it also varies with season. Because of the earth’s tilt, during the northern summer the sun is overhead at the Tropic of Cancer, and the Artic regions receive insolation 24 hours per day. However, in the northern winter, the sun does not shine on the Artic, so there is no insolation at all.

Factors Affecting Insolation
The Green House Effect p3

What were the key points for ‘Variations in Isolation’
Albedo Affect Equator’s surface – low reflection (high insolation) Pole’s surface – high reflection (high terrestrial radiation) (land cover) Earth’s tilt Earth’s orbit around the sun Winter solstice – polar region – no solar insolation Tropics – yearly solar insolation Earth is a sphere Concentrated rays at equator Intensity from vertical rays

Atmospheric Circulation
Atmosphere Atmospheric Circulation This diagram shows how heat from the Equatorial area is transferred to the polar regions by the circulation of the atmosphere in the Northern Hemisphere.

THE THREE CELL MODEL;-FORMATION OF THE HADLEY CELL (1)
ATMOSPHERE CELLS AND HEAT TRANSFER A single cell model like in diagram 9 is too simplistic- we can find three interlinked cells! THE THREE CELL MODEL;-FORMATION OF THE HADLEY CELL (1) Insolation in tropical areas causes warm air to rise and spread polewards, carrying heat energy. SOLAR ENERY INSOLATION Nb; lots of new terms to learn!

FORMATION OF THE HADLEY CELL (2)
ATMOSPHERE FORMATION OF THE HADLEY CELL (2) Air cools and begins to fall at about 30ºN and 30ºS of Equator. Cooled air returns to the Equator. NORTHERN HADLEY CELL. SOLAR ENERGY Heat energy is therefore transferred from the Equator to sub-tropical latitudes. SOUTHERN HADLEY CELL.

FORMATION OF THE POLAR CELL (1)
ATMOSPHERE FORMATION OF THE POLAR CELL (1) Intensely cold, dense air sinks at the poles, then blows as surface winds towards the Equator.

FORMATION OF THE POLAR CELL (2)
ATMOSPHERE FORMATION OF THE POLAR CELL (2) At about 60ºN and 60 ºS, the cold polar air is warmed in contact with the earth’s surface. NORTHERN POLAR CELLS. SOUTHERN POLAR CELLS. This warmed air rises and returns polewards, carrying heat energy. This circular motion is called the POLAR CELL.

FORMATION OF THE FERREL CELL
ATMOSPHERE FORMATION OF THE FERREL CELL Unlike the Hadley and Polar Cells, the Ferrel Cell is not driven by differences in heat energy. The Ferrel Cell is caused by friction where air is in contact with the other two cells. (The Hadley Cell drags air down at about 30ºN and S. The Polar Cell causes an uplift at about 60ºN and S. )

THE THREE CELLS TOGETHER
ATMOSPHERE Polar Cell THE THREE CELLS TOGETHER Ferrel Cell Hadley Cell Hadley Cell Ferrel Cell Polar Cell

ATMOSPHERE It is well worth making sure that you can see the rising and falling pattern of these cells. The next section uses this to work out wind directions on the surface of the earth. There are handouts of the next few slides; use them and diagram 13 to answer the later questions on the screen.

ASSOCIATED PRESSURE BELTS
ATMOSPHERE ASSOCIATED PRESSURE BELTS HANDOUT Rising air at the equator causes the equatorial belt of low pressure Polar high pressure Mid latitude low pressure Descending air at about 30ºN and 30ºS causes the sub-tropical belt of high pressure Sub-tropical high pressure Equatorial low pressure Rising air at about 60ºN and 60ºS causes a mid-latitude belt of low pressure Sub-tropical high pressure Mid latitude low pressure Descending air at the poles causes the polar high pressure areas Polar high pressure

ASSOCIATED SURFACE WIND PATTERNS
ATMOSPHERE ASSOCIATED SURFACE WIND PATTERNS COPY TEXT Winds always blow from high pressure to low pressure. They are deflected because of the Coriolis Force which come about because of the rotation of the earth. ( see later slide) HANDOUT Polar high pressure Mid latitude low pressure Sub-tropical high pressure Winds in Northern Hemisphere are deflected to the right. Equatorial low pressure Winds in the southern hemisphere are deflected to the left. Sub-tropical high pressure Mid latitude low pressure These wind belts shift seasonally. (See next section) Polar high pressure

Answer these five questions fully in sentences.
ATMOSPHERE Answer these five questions fully in sentences. Q1. What kind of pressure has rising air? Low pressure has rising air. Q2. What kind of pressure has falling air? High pressure has falling air. Q3. Name two latitudes with rising air. The Equator and 60 degrees N/S have rising air. Q4. Name two latitudes with falling air. 30 degrees N/S and the Poles have falling air.

ATMOSPHERE Q5. Explain the two factors that make the NE trade winds blow in the direction they do. ( You will need to be able to do this for any of the winds in diagram 13 !) i) Air is flowing from a high pressure area at 30 degrees north towards a low pressure area at the Equator. ii). The winds are being deflected by the Coriolis force/ effect to the right as the area is in the northern hemisphere.

Rossby waves and the Jet Stream
ATMOSPHERE Rossby waves and the Jet Stream Not far above our heads in the northern UK is where the Ferrel and Polar cells meet. Here is where powerful waves of turbulence occur called Rossby waves. This turbulence is mainly responsible for the series of depressions and anticyclones that happen over Britain. Read about these on pages 10 and 11, then answer the questions on the next slide.

Q1. In what direction do Rossby waves flow in the northern hemisphere?
ATMOSPHERE Q1. In what direction do Rossby waves flow in the northern hemisphere? They flow towards the east in the northern hemisphere. Q2. What is the name of the contact zone between the two cells? A. It is called the Polar Front. Q3. In what way is stage 4 like the formation of a river’s ox-bow lake ? A. Loops of turbulence get cut- off and isolated from the main flow.

What happens when you set off in a plane to fly to somewhere?
ATMOSPHERE Q4.In what way is the Ferrel cell thought to be less effective in atmospheric heat transfer? A. It seems that winds and ocean currents transfer more heat than this weak atmospheric cell. THE CORIOLIS FORCE. What happens when you set off in a plane to fly to somewhere? The earth turns beneath you, and you have to keep adjusting your direction ! Watch……….

Got the idea? Note the runners path is curved!
ATMOSPHERE Destination has moved Direction of Earth-spin Got the idea? Note the runners path is curved! New direction Destination has moved New direction Thirty minutes in Twenty minutes in Destination has moved New direction Ten minutes in start destination Initial direction

Pages 14 and 15 are very technical !
ATMOSPHERE Pages 14 and 15 are very technical ! The information is of the kind that can give extra marks in an extended answer. Ignore it at your peril ! We suggest that you read it at home where you can think deeply about it ! You will need to have a basic understanding of why the wind belts are in different places at different times of the year.

Atmosphere Ocean Currents

Atmosphere Ocean Currents
You need to know how the ocean currents work in one ocean. The Atlantic will do. You need to remember the names of the currents and the directions in which they travel. You must know whether they are hot or cold. Note how the ocean currents also obey the Coriolis Force Laws.

Atmospheric Circulation
Atmosphere Atmospheric Circulation So far, we have concentrated on the circulation of the air throughout the depth of the atmosphere. Now it is time to look in detail at air movements near the earth’s surface. It is easier to understand and remember this movement if we start with the global pressure belts. In theory, the global pressure belts are perfectly balanced north and south of the Equator.

The Main Global Pressure Belts
Atmosphere The Main Global Pressure Belts There is a band of Low Pressure at the equator. There are two bands of High Pressure between 300 and 400 north and south of the Equator. There are two bands of Low Pressure around 600 north and south of the Equator. There are two bands of High Pressure over the North and South Poles.

OCEAN CURRENTS and HEAT TRANSFER
ATMOSPHERE OCEAN CURRENTS and HEAT TRANSFER Water heats up and cools down very slowly. But once it has stored it, it holds on to that temperature for a long time. As currents move, they transport heat and cold around the globe.

Land masses disrupt an otherwise straight-forward water flow pattern.
ATMOSPHERE The pattern of ocean currents is linked to the pressure belts and wind patterns. Land masses disrupt an otherwise straight-forward water flow pattern. Winds blowing over currents assist them in transferring heat from warm to cool areas and vice versa. Winds deflected by the Coriolis force help to create the currents. The nature of the current affects the land masses it flows beside. Copy this

Read pages 16-18 and then answer the questions on the slides.
ATMOSPHERE Read pages and then answer the questions on the slides. Q1. What sets off ocean currents? Surface prevailing winds set off most currents. Q2. In what direction does a northern hemisphere current bend, and why? A. It bends to the right due to the Coriolis effect. Q3. What happens to the coldest ,densest water at the Poles? A. It sinks to the ocean floor and returns to the Equator below the warmer water layer.

Q4. What happens therefore to warmer, lighter water?
ATMOSPHERE Q4. What happens therefore to warmer, lighter water? A. It rises to the surface and flows away from the Equator. (i.e. A convection cell is created ! ) Q5. What is a gyre? A. It is a three-dimensional circular flow of water. Q6. In which directions do each flow? In the northern hemisphere, clockwise ( and v.v.). Is this the same as bathwater down your plug? Do this for homework !

Q7. Give an example of a current which;-
ATMOSPHERE Q7. Give an example of a current which;- Is warm, coast-hugging and in the Northern hemisphere. Is cool, coast-hugging and in the Northern hemisphere. c) Is warm, coast-hugging and in the Southern hemisphere. d) Is cool, coast-hugging and in the Southern hemisphere. e). A high- latitude gyre. Q8. Why is the Antarctic current so simplistic?

Colour your diagram 17 map as follows;-
ATMOSPHERE Colour your diagram 17 map as follows;- Blue for the cold currents Red for the warm currents Yellow for coasts warmed by a current Green for coasts cooled by a current.

ATMOSPHERE

CASE STUDY AREA- the ITCZ in AFRICA
ATMOSPHERE CASE STUDY AREA- the ITCZ in AFRICA You will need to be able to give very detailed answers to a question on this area in an assessment. This case study shows the way that the movement of the wind belts between their summer and winter positions has a profound effect on the lives – indeed the very survival- of people who live in the Sahel zone of northern Africa. You will need an atlas for most of this section. Get one now.

ATMOSPHERE The ITCZ is an area where two air masses meet- it brings heavy rain to the areas it passes over. It happens all round the world between the Equator and about 20 degrees N/S. Its full name is the Inter Tropical Convergence Zone. It is part of the Hadley convection cells, and has the Doldrums within its boundary. Copy text

There is a handout of the text from the next few slides.
ATMOSPHERE The AFRICAN ITCZ REGION The ITCZ does not stay in the same area all year round but migrates to the north and then back south again. It is this movement that matters so much to the people and animals of the area. Discuss this diagram There is a handout of the text from the next few slides.

The clusters are particularly found over land, not sea.
ATMOSPHERE The trade winds ( mT air mass) come into the zone from cooler areas in the southern mid- latitudes and have travelled over oceans; they are there fore carrying a lot of moisture This is their position in January. Once in the hotter latitudes, they are energised into huge towering cumulo-nimbus thunderclouds. These can be anything up to 10kms across, and groups of clouds can form covering 1000kms. In between the clusters are often sunny cloud-free areas. The clusters are particularly found over land, not sea.

Coastal areas- equatorial climate Inland areas- savanna climate type
ATMOSPHERE IN JANUARY N S Hot dry cT air Wet warm mT air HEAVY RAINS Moves this way ‘Harmattan’ wind Gulf of Guinea Coastal areas- equatorial climate Inland areas- savanna climate type Sahara- Desert climate type Copy diagram

The ITCZ zone of meeting air lies well to the south, as seen here.
ATMOSPHERE In January, the sun is overhead near the Tropic of Capricorn, in the southern hemisphere. The ITCZ zone of meeting air lies well to the south, as seen here. The rains brought by the zone are confined to the very coastal areas of Nigeria, Togo, Ghana and their neighbours. Case study area ITCZ JANUARY

Atmosphere The Inter Tropical Convergence Zone- The ITCZ July
The movement of the ITCZ and its effects on rainfall can be best understood by examining the situation in Africa. 23.50N Equator July NE Trade Winds 23.50N 23.50S Equator Warm, Dry Winds (cT) Warm, Dry Winds Warm, Moist Winds (mT) The ITCZ in Africa In July SE Trade Winds Warm, Moist Winds The ITCZ in Africa In January 23.50S January

Atmosphere The Changing ITCZ July September November
The ITCZ moves north and south over Africa to “follow the sun”. However, the ITCZ sticks over the land areas since the land is warmer than the sea causing lower pressure over he land than over the area. ITCZ ITCZ ITCZ July September November

Atmosphere The Changing ITCZ January March May
The ITCZ moves north and south over Africa to “follow the sun”. However, the ITCZ sticks over the land areas since the land is warmer than the sea causing lower pressure over he land than over the area. ITCZ ITCZ ITCZ January March May

ATMOSPHERE Here, the moist warm mT air from the Atlantic Ocean meets the hot dry cT air coming out of the Sahara Desert. Note that the desert is an area of HIGH pressure in winter and particularly strong winds blow AWAY from such areas. The cT wind is called the HARMATTAN and is extremely hot, dry and dusty. Of course, the Harmattan cannot bring any rain to the area it travels over, and all the northern part of Africa is influenced totally by it. No crops can grow. In the south, however, the wet moist winds from the sea are forced upwards over the land where they drench the land in life-giving torrential rains. Here crops can be easily grown, providing the soil is fertile enough and not washed away.

ATMOSPHERE During the spring, the ITCZ moves slowly northwards, the Harmattan losing its dominance over the land bit by bit. Places further and further inland get the rains that they so desperately need for people, crops and animals alike. The slight drawback is that the further the ITCZ travels north, the less water it can bring to the rainy area, so crops to the north get less than those to the south. By mid spring, places like northern Ghana, northern Benin and central Nigeria are getting the rains. The wells are re-filled, the grass for feeding animals starts to grow and farmers can start off their crops.

Coastal areas- equatorial climate Inland areas- savanna climate type
ATMOSPHERE IN JULY S N Compare the January and July diagrams. Hot dry cT air Wet warm mT air Moves this way ‘Harmattan’ wind HEAVY RAINS LIGHT RAINS Gulf of Guinea Coastal areas- equatorial climate Inland areas- savanna climate type Sahara- Desert climate type Copy diagram

ATMOSPHERE There is a handout illustrating the two main climate types mentioned on the previous slide, affected by the ITCZ. You will need to be able to recognise the differences between them in an exam question.

ATMOSPHERE By July the ITCZ has reached as far north as it will go, reaching central Mali, northern Niger and northern Chad. There the Harmattan is confined to the very edges of the Sahara desert, the weakest it gets all year. This is the Sahel zone, the area most prone to DESERTIFICATION that you learned about in Standard Grade. Without these rains most years, the desert will take over yet more land, forcing poverty-stricken, hungry people to migrate southwards into other peoples’ territory, with their thirsty cattle and goats. ITCZ JULY

No more rain will fall this far inland until next year!
ATMOSPHERE After July, the belt moves back down south again, giving a second rainy spell to the lucky areas in its path. No more rain will fall this far inland until next year! The people rely on these rains that arrive within a week or two of the same time every year. Recently, there have been several years where the rain has not got as far inland as normal ! What do you think has been the result of this?

Answer the 12 questions in your jotters.
ATMOSPHERE Read the article on the handout which highlights the human consequences of the failure of this pattern of rainfall. Answer the 12 questions in your jotters.

Lesley Monk Balfron High School Session 2005/6
ATMOSPHERE Lesley Monk Balfron High School Session 2005/6

GLOBAL WARMING – ARE WE TO BLAME ?
ATMOSPHERE GLOBAL WARMING – ARE WE TO BLAME ? This is one of the most frequently asked environmental questions in recent times. That the planet’s climate is changing, there is no doubt. But who or what is the reason for this is a hotly debated point. We shall put the evidence in front of you and let you decide! We really don’t know ! So what is the answer ?

Graph 3 shows the time since the Vikings began raiding Britain.
ATMOSPHERE Graph 1 shows the temperature of the Earth over 1 million years. Note the line showing today’s average temperatures, and the arrow to the last Ice Age. Graph 2 is a close-up from the last few years of the Ice Age till today. Graph 3 shows the time since the Vikings began raiding Britain.

ATMOSPHERE 1. ICE CORE ANALYSIS-Air trapped in ancient snow- now ice- can show what the atmosphere was like millions of years ago. 2. TREE RING ANALYSIS- Tree rings record good and bad years for tree growth and can go back to prehistoric times. WHAT EVIDENCE IS THERE OF GLOBAL WARMING ? 4. POLLEN ANALYSIS-This will show the types of plants that were growing in an area millions of years ago, and we can work out the likely conditions from comparison with today’s plant needs. Copy text 3. OCEAN FLOOR SEDIMENTS-The mud in the ocean deep has been there for millennia and can be analysed for oxygen isotopes.

So you can see that our planet hasn’t exactly had a stable climate !
ATMOSPHERE So you can see that our planet hasn’t exactly had a stable climate ! But are we responsible for the changes, or is it natural forces at work? Read pages 25 and 26 of the booklet. You will need to be able to discuss each of these factors in a way that shows you appreciate their potential importance.

Physical Factors Human Factors Solar variation Burning fossil fuels
ATMOSPHERE There are different possible causes of these raised temperatures. They fall into two categories- Physical and Human. Physical Factors Solar variation Volcanic activity Ocean currents Milankovitch cycles Human Factors Burning fossil fuels Increased output of methane etc. Deforestation Let’s look at each in turn.

PHYSICAL 1 - SOLAR VARIATION
ATMOSPHERE PHYSICAL 1 - SOLAR VARIATION Sunspots: an increase in sunspot activity may lead to a very slight increase in the sun’s output and a temporary warming of the earth. Sunspot activity follows 11 and 22 year cycles. The Little Ice Age of may have been linked to periods of very low sunspot activity.

PHYSICAL 2 - VOLCANIC ERUPTIONS
ATMOSPHERE PHYSICAL 2 - VOLCANIC ERUPTIONS Eruptions of volcanoes can throw millions of tonnes of ash,dust and sulphur dioxide into the atmosphere. This produces aerosols that can reduce the amount of sunlight reaching the earth. This can lead to a temporary cooling of the earth.

ATMOSPHERE VOLCANIC ERUPTIONS 2 Major eruptions in the past which have been linked to short periods of global cooling include;- Tambora (1815), Krakatoa (1883), Mt. St Helens (1980) Pinatubo (1991)

PHYSICAL 3 – OCEAN CURRENTS
ATMOSPHERE PHYSICAL 3 – OCEAN CURRENTS Changes in the pattern and strength of ocean currents may lead to changes in the distribution of heat around the planet. A short term example would be El Niño, which appears every few years. A longer term example would be the North Atlantic Drift, which may change position every few thousand years.

ENSO - the El Niño Southern Oscillation
ATMOSPHERE ENSO - the El Niño Southern Oscillation Every 2-7 years the western Pacific becomes much warmer, disrupting weather patterns - possibly on a global scale. The “normal” conditions, with cool surface water off the coast of Peru. A La Niña year An El Niño year

ATMOSPHERE One theory suggests that global warming will increase the number of icebergs in the Atlantic, cooling the sea and switching off the North Atlantic Drift / Atlantic Conveyor system. This would be bad news for us!

PHYSICAL 4 - MILANKOVITCH CYCLES
ATMOSPHERE PHYSICAL 4 - MILANKOVITCH CYCLES Milankovitch cycles are three variations in the earth’s orbit. Although they may be linked to very long term changes in the climate, their effect would not be noticed on a scale of a few hundred years.

HUMAN FACTORS THE ENHANCED GREENHOUSE EFFECT.
ATMOSPHERE HUMAN FACTORS THE ENHANCED GREENHOUSE EFFECT.

These are the main greenhouse gases
ATMOSPHERE These are the main greenhouse gases See how they have increased over the years of industrial activity. HOW ?

HUMAN 1 - BURNING FOSSIL FUELS
ATMOSPHERE HUMAN 1 - BURNING FOSSIL FUELS The fossil fuels are:- COAL OIL NATURAL GAS They are called fossil fuels because they are formed from the remains of ancient plants (coal) and marine animals (oil).

ATMOSPHERE When we burn these fuels, we release millions of tonnes of Carbon Dioxide (CO2) into the atmosphere. There has been an enormous increase in these greenhouse gases since the Industrial Revolution began about 200 years ago.

ATMOSPHERE Power stations are one of the main producers of greenhouse gases such as Carbon Dioxide.

ATMOSPHERE Environmental campaigners all over the world are demanding cuts in CO2 emissions. Here Greenpeace uses a light display to get its message across.

Vehicle exhausts are the main source of Nitrous Oxides.
ATMOSPHERE Vehicle exhausts are the main source of Nitrous Oxides.

HUMAN 2 - INCREASED METHANE
ATMOSPHERE I am a ruminant - when I digest grass, I produce methane - lots of it! HUMAN 2 - INCREASED METHANE A cow can burp / fart about a quarter of a kg. of methane a day. The number of cattle has doubled in the past 40 years. Sheep, goats and camels are also ruminants. There are now 1.3 billion cattle, each burping / farting methane several times a minute! The New Zealand government is proposing to bring in a “flatulence” tax on cattle farms.

ATMOSPHERE The huge increase in world population and in the area of land given over to crops in general and to rice production in particular, has led to a rapid rise in global methane production. Farmland for rice has doubled in 45 years.

Forests absorb CO2 and release oxygen:
ATMOSPHERE HUMAN 3 - DEFORESTATION Forests absorb CO2 and release oxygen: ...if they are cut down, atmospheric levels of CO2 must rise as a consequence.

The smoke from the fires also adds to global air pollution.
ATMOSPHERE Clearing forest by burning releases huge amounts of stored CO2 back into the atmosphere. The smoke from the fires also adds to global air pollution. This is known as a double- whammy !

Solar variation / Sunspots
ATMOSPHERE KEY TERMS TO REMEMBER Solar variation / Sunspots Volcanic eruptions /Sulphur dioxide /Aerosols Milankovitch cycles El Niño Enhanced Greenhouse effect Carbon Dioxide / Methane / Nitrous Oxides The Industrial Revolution / burning fossil fuels Padi fields / cattle / methane production Deforestation

CONGRATULATIONS !! You have now finished the Higher Geography Course!
All that remains is to learn it all!

Lesley Monk Balfron High School Session 2005/6

Energy budget diagrams
ATMOSPHERE REVISION Energy budget diagrams like in slide 4 There are only a few types of questions they ask about;- The principles of energy movement around the planet Cells and the way they move heat around- not done for a few years ! The contribution made by ocean currents to heat transfer.

The principles explained
ATMOSPHERE REVISION The principles explained The ITCZ and its effects Data like maps and graphs described and explained.

fluctuation graph described and explained
ATMOSPHERE REVISION World temperature fluctuation graph described and explained The causes and effects of climate change, including global warming. The human and physical causes of the greenhouse effect named and explained. These are often combined!

ATMOSPHERE REVISION Energy budget diagam- Describe and explain the exchanges that result in only 50% of the potential Sun’s energy reaching the surface. (4)

Atmospheric winds circulation diagram
ATMOSPHERE REVISION Atmospheric winds circulation diagram Explain how the cells A,B and C, and their associated surface winds, help to distribute energy around the Earth. (4)

Ocean circulation diagram
ATMOSPHERE REVISION Ocean circulation diagram Explain how the ocean currents operate to maintain an energy balance. (3 or 4 ) This question has been known to focus on one ocean only to explain !

The principles of the ITCZ
ATMOSPHERE REVISION The principles of the ITCZ Using the information on the maps and the graph, and referring to the characteristics of the two air masses shown, describe and account for the annual seasonal variations in rainfall in West Africa. (4)

ATMOSPHERE REVISION The effects of the ITCZ Describe in detail and account for the pattern of annual rainfall shown in the diagrams. (5)

World temperature fluctuation graph described and explained
ATMOSPHERE REVISION Describe and give both human and physical reasons for the fluctuation in world temperatures shown in the graph. (5)

Higher Geography Atmosphere

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