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Higher Geography
Atmosphere
ATMOSPHERE
INTRODUCTION
Skin cancers
Global warming
Atmosphere
in the news
Hole in the
ozone layer
Climate change
Acid rain
Greenhouse
gases
CFC’s
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
Topic
Topic
Topic
Topic
1: Global Insolation
2: Atmospheric Circulation
3: Oceanic Circulation
4: Air Masses
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. 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 50-90km (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. 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. 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.
ATMOSPHERE
SOLAR INSOLATION
reflected by clouds
and dust, water vapour and other gases
in the atmosphere
100%
25%
23%
absorbed by clouds
and dust, water vapour and other gases in the atmosphere
52%
reflected by surface
6%
absorbed by surface
46%
earth
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.
AGAIN, COPY AND
MEMORISE THIS
DIAGRAM!
The band at the equator can
concentrate its heat in a
smaller area A-B
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
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.
ATMOSPHERE
CELLS AND HEAT TRANSFER
A single cell model like in diagram 9 is too simplisticwe 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.
INSOLATION
SOLAR
ENERY
Nb; lots of new
terms to learn!
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.
ATMOSPHERE
FORMATION OF THE POLAR CELL (1)
Intensely cold,
dense air sinks at
the poles, then
blows as surface
winds towards the
Equator.
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.
This warmed air rises and
returns polewards,
carrying heat energy.
SOUTHERN POLAR CELLS.
This circular motion is
called the POLAR 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. )
ATMOSPHERE
THE THREE
CELLS
TOGETHER
Polar Cell
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.
ATMOSPHERE
ASSOCIATED PRESSURE BELTS
HANDOUT
Rising air at the equator
causes the equatorial belt of
low pressure
Descending air at about
30ºN and 30ºS causes the
sub-tropical belt of high
pressure
Polar high pressure
Mid latitude low pressure
Sub-tropical high pressure
Equatorial low pressure
Rising air at about 60ºN
and 60ºS causes a midlatitude belt of low
pressure
Descending air at the
poles causes the polar high
pressure areas
Sub-tropical high pressure
Mid latitude low pressure
Polar high pressure
ATMOSPHERE
ASSOCIATED SURFACE WIND PATTERNS
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
COPY
TEXT
Winds in Northern
Hemisphere are deflected to
the right.
Winds in the southern
hemisphere are deflected to
the left.
These wind belts shift
seasonally. (See next section)
Polar high pressure
Mid latitude low pressure
Sub-tropical high pressure
Equatorial low pressure
Sub-tropical high pressure
Mid latitude low pressure
Polar high pressure
ATMOSPHERE
Answer these five questions fully in sentences.
Q1. What kind of pressure has rising air?
A.Low pressure has rising air.
Q2. What kind of pressure has falling air?
A.High pressure has falling air.
Q3. Name two latitudes with rising air.
A.The Equator and 60 degrees N/S have rising air.
Q4. Name two latitudes with falling air.
A.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.
ATMOSPHERE
Rossby waves and the Jet Stream
Not far above our
heads in the
northern UK is
where the Ferrel
and Polar cells meet.
This turbulence is
mainly responsible for
the series of
depressions and
anticyclones that
happen over Britain.
Here is where
powerful waves of
turbulence occur
called Rossby waves.
Read about these on
pages 10 and 11,
then answer the
questions on the
next slide.
ATMOSPHERE
Q1. In what direction do Rossby waves flow in the
northern hemisphere?
A.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.
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……….
ATMOSPHERE
Destination
Direction of Earth-spin
has moved
Got the idea?
Note the
runners path is
curved!
Destination
has moved
Thirty
minutes in
Twenty
minutes in
Destination
has moved
Ten
minutes in
Initial direction
start
destination
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.
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.
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.
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.
ATMOSPHERE
The pattern of ocean currents is linked to
the pressure belts and wind patterns.
Land masses disrupt an otherwise straightforward 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
ATMOSPHERE
Read pages 16-18 and then answer the
questions on the slides.
Q1. What sets off ocean currents?
A.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.
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?
A.In the northern hemisphere, clockwise ( and v.v.).
Is this the same as bathwater down your plug? Do
this for homework !
ATMOSPHERE
Q7. Give an example of a current which;a) Is warm, coast-hugging and in the Northern
hemisphere.
b) 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?
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
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.
Copy text
Its full name is the
Inter Tropical
Convergence Zone. It is
part of the Hadley
convection cells, and has
the Doldrums within its
boundary.
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.
Discuss
It is this
this
movement that
diagram
matters so much
to the people and
animals of the
area.
There is a handout of the text from
the next few slides.
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 therefore 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.
ATMOSPHERE
S
Wet
warm
mT air
IN JANUARY
N
Hot
dry
cT
air
Moves this way
‘Harmattan’ wind
HEAVY RAINS
Gulf of
Guinea
Coastal
areasequatorial
climate
Inland areassavanna
climate type
Copy diagram
SaharaDesert
climate
type
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
The movement of the ITCZ and its effects on rainfall can be best
understood by examining the situation in Africa.
23.50N
NE Trade Winds
Warm, Dry Winds (cT)
23.50N
Warm, Dry Winds
Warm, Moist Winds (mT)
Equator
SE Trade Winds
23.50S
July
The ITCZ in
Africa In July
Equator
Warm, Moist Winds
23.50S
January
The ITCZ in
Africa In
January
Atmosphere
The Changing ITCZ
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
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
January
ITCZ
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.
ATMOSPHERE
S
IN JULY
Compare the January and July diagrams.
Hot
dry
cT
air
Wet
warm
mT air
Moves this way
HEAVY RAINS
Gulf of
Guinea
Coastal
areasequatorial
climate
N
‘Harmattan’ wind
LIGHT RAINS
Inland areassavanna
climate type
Copy diagram
SaharaDesert
climate
type
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
ITCZ JULY
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.
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?
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.
ATMOSPHERE
Lesley Monk
Balfron High School
Session 2005/6
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!
So what is the
answer ?
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 ANALYSISAir trapped in ancient
snow- now ice- can show
what the atmosphere was
like millions of years ago.
2. TREE RING ANALYSISTree rings record good and
bad years for tree growth
and can go back to
prehistoric times.
WHAT EVIDENCE IS THERE OF GLOBAL WARMING ?
Copy text
3. OCEAN FLOOR
SEDIMENTS-The mud in
the ocean deep has been
there for millennia and can
be analysed for oxygen
isotopes.
4. POLLEN ANALYSISThis 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.
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.
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.
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 14501700 may have been linked to
periods of very low sunspot
activity.
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)
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.
ATMOSPHERE
ENSO - the El Niño Southern Oscillation
The “normal” conditions,
with cool surface water off
the coast of Peru.
A La Niña year
Every 2-7 years the western
Pacific becomes much warmer,
disrupting weather patterns possibly on a global scale.
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!
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.
ATMOSPHERE
HUMAN FACTORS
THE ENHANCED GREENHOUSE EFFECT.
ATMOSPHERE
These are the main
greenhouse gases
See how they have
increased over the
years of industrial
activity.
HOW ?
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.
ATMOSPHERE
Vehicle
exhausts are
the main
source of
Nitrous
Oxides.
ATMOSPHERE
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.
I am a
ruminant when I
digest
grass, I
produce
methane lots of it!
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.
ATMOSPHERE
HUMAN 3 - DEFORESTATION
Forests absorb CO2 and
release oxygen:
...if they are cut down, atmospheric levels of CO2 must rise as
a consequence.
ATMOSPHERE
This is known as a
double- whammy !
• 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.
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
ATMOSPHERE REVISION
There are only a few
types of questions
they ask about;-
The principles
of energy movement
around the planet
Energy budget diagrams
like in slide 4
Cells and the way
they move heat aroundnot done for a few years !
The contribution made
by ocean currents to
heat transfer.
ATMOSPHERE REVISION
The principles explained
The ITCZ and
its effects
Data like maps and
graphs described and
explained.
ATMOSPHERE REVISION
The causes and
effects of climate
change, including
global warming.
World temperature
fluctuation graph described
and explained
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)
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)
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 !
ATMOSPHERE REVISION
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)
The principles
of the ITCZ
ATMOSPHERE REVISION
The effects
of the ITCZ
Describe in
detail and
account for
the pattern of
annual rainfall
shown in the
diagrams. (5)
ATMOSPHERE REVISION
World temperature
fluctuation graph
described
and explained
Describe and give both human and physical reasons
for the fluctuation in world temperatures shown in
the graph. (5)