Transcript Higher Atmosphere MearnsPW

Higher Atmosphere
Earth’s Heat Budget
Global Insolation
Global Transfer Of Energy
Global Temperatures
Inter Tropical Convergence Zone
Climate Graph
26% Reflected
(Albedo) By
Clouds
100% Short
Wave Solar
Energy
(Insolation)
Limit Of
Atmosphere
18% Absorbed
By Atmosphere
6% Reflected
(Albedo) By Earths
Surface (Long Wave)
50% Absorbed By
Earths Surface
26% Reflected
(Albedo) By
Clouds
100% Short
Wave Solar
Energy
(Insolation)
Limit Of
Atmosphere
18% Absorbed
By Atmosphere
6% Reflected
(Albedo) By Earths
Surface (Long Wave)
50% Absorbed By
Earths Surface
SOLAR INSOLATION IN EARTHS HEAT BUDGET
100% solar insolation
26% reflected by atmosphere
18%
absorbed by atmosphere
56% reaches surface
6%
reflected by surface
50% absorbed by surface
TOTAL ALBEDO = 26 + 6
= 32%
TOTAL ABSORPTION = 18 + 50
= 68%
The Heat Budget
• Only 50% of the incoming solar radiation
(insolation) which reaches the atmosphere
from the sun, actually penetrates to the
surface of the earth.
• Energy which is lost is done so in 2 ways
through reflection and through absorption.
Earth’s Heat Budget
Earth’s Heat
Budget
Insolation
(Task 2)
This is incoming solar energy (heat).
This is energy or heat emitted
from the earth, only 6% escapes
the earth the rest being absorbed
into the atmosphere.
Albedo
This is the total amount of energy
reflected from the earth.
Long Wave
Radiation
This is the balance between incoming
and outcoming energy.
The Earth’s Heat Budget
To help you, use the following structure.
Say where the earths energy come from and name it.
Briefly explain what the earth’s heat budget is.
Describe what happens to the insolation giving values;
•Atmospheric absorption (clouds)
•Atmospheric reflection (albedo + clouds)
•Surface absorption (land)
•Surface reflection (albedo + ice/water)
Earth’s Heat Budget
(Task 3)
The earths energy comes from solarradiation, this incoming
heat energy is balanced by the amount of heatescaping back
into space. This balance is called the earthsheat budget.
Incoming solar heat (insolation) from the sun is absorbed and
reflected meaning not all the heat reachesthe earths surface.
26% of the energy isreflected back into space by the earths
atmosphereand 18% of the heat isabsorbed by the
atmosphere due to dust particlesretaining the heat.
This leaves 56% which travels to the earthssurface. Not all of
this is absorbed 6% is reflected from the earths surface by
polar ice caps& water, and thismakes up part of the earths
Albedo. This means only 50%reaches the earths surface and
is balanced out by the long wave radiationescaping back into
the atmosphere.
Variations in Global
Temperatures
• To understand the reasons as to why
the poles are in deficit and the
equatorial regions have an energy
surplus
Global Insolation
The Earth's atmosphere is put into motion because of
the differential heating of the Earth’s surface by
solar insolation.
This means that the winds and clouds above us move
around because there are some areas of the earth
which are hotter than others.
We therefore need to know why these difference
occur, so we can then study the different
movements of the weather in the atmosphere. This
then lets us make accurate weather forecasts.
Variations in Insolation
• The amount of insolation at the Earth’s
surface varies according to latitude – most
heat is received at the Tropics and least
heat is received at the Poles.
• As a result, there is a net gain of solar
energy in the tropical latitudes and a net
loss towards the poles.
Reasons for Variations in Insolation
• Surface area to be covered is greater at
Poles than Tropics so more insolation lost at
Poles.
• More atmosphere to pass through at Poles
than Tropics so more insolation lost at Poles.
• Position of sun – the sun is high in sky all year
round at Topics whereas at Poles there is no
insolation for 6 months of the year.
• Albedo. Snow and ice covered Poles reflect
insolation. Forested Tropics absorb it.
Global Insolation
High
Albedo
Task 4 (1)
Different
Differing
Depths
Of Curvature
Atmosphere
Insolation
Low
Differing
Albedos
Albedo
Energy From
The Sun
Global Insolation Task 4 (1)
High
Albedo
Different
Curvature
Insolation
Low
Albedo
Differing Depths
Of Atmosphere
Task 5 Latitude & Distribution
Of Solar Energy
Distance: Insolation from the sun travels different distances, and
hence amounts of air, because of the curvature of the earth. At the
equator there is a shorter distance to travel, but at the poles there is
a greater distance to reach the land. This means that the insolation
will be weakened more approaching the poles than at the equator and
Curvature:
The at
curvature
of the earth also has an effect on the
so make it cooler
the poles.
distribution of solar energy. The sun’s rays are more concentrated at
the equator so it is hotter or has more solar energy. At the poles the
same rays are spread over a greater distance so there heat is spread
making it cooler. The poles therefore have less solar energy than the
Albedo: The high quantities of ice at the poles mean there is a high
equatorial regions.
albedo (reflection), so that insolation is reflected and the poles
receive less solar heat/radiation. The equatorial regions have high
concentrations of rainforest, the dark green colour absorbing
insolation and so receive more heat.
Variations In Global Insolation
WithDescribe
the aid of an
annotated diagram describe
Range of latitude
and explain the energy
shown
35°
35°balance
to
to 0°
90°N
(N or Sonof)
ofthe
Equ.
Equ.
diagram below.
State
Stateififinindeficit
deficitororsurplus
surplus
Givevalues
valuesininJoules
Joules170
50 to
to 270
170
Give
Variations In Global Insolation
Explain In Detail
Why deficit in high latitudes
(polar areas) and why surplus in
low latitudes (equatorial areas)
Insolation - distance travelled
through atmosphere greater
at poles so heat lost
Concentration of insolation
higher at equator due to
curvature of earth
Albedo high at poles and low
at equator
Global Transfer Of Energy
This is the movement of energy from the equator to
the poles. Global Insolation differences should mean
that the lower latitudes (equator) get hotter and
hotter, whilst the higher latitudes (poles) get colder
and colder.
In reality this doesn’t quite happen as energy is
transferred from surplus areas (equator) to deficit
areas (poles) by two methods.
Atmospheric Circulation & Ocean Currents
Atmospheric
Circulation
(Task 7)
Finally the cool
air sinks at the
poles having
distributed heat
from the equator
to the poles
The air warms
again and so
rises giving rain
The cool air then
starts to fall back
to the earth
Hot air at the
equator rises
This cools as it
rises giving cloud
and then rain
C
90N°
60N°
B
30N°
A
0°
A = Hadley Cell
B =inFerrel
CellA, B & C.
Colour
the cells
C = Polar Cell
Atmospheric Circulation Cells
The three weather cells.
The Hadley Cell ~ this circulates air between the
equator 0° and the tropics of, Capricorn in the
south (30°S) & Cancer in the north (30°N).
The Polar Cell ~ this circulates air between the
North Pole & the Arctic circle (90°N & 60°N)
The Ferrel Cell ~ this isn’t actually a cell but
circulates air through friction between the tropic of
Cancer & Arctic Circle in the North (30°N &
60°N) and the Tropic of Capricorn & Antarctic
Circle in the south (30°S & 60°N)
Atmospheric Circulation Hadley Cell
Equatorial Low
Pressure
Sub Tropical
High Pressure
Sub Tropical
High Pressure
Atmospheric Circulation Polar Cell
Cool air falls at the poles.
Polar High Pressure
90°N
The air spreads south,
warmed by the sea and land.
As the air rises
it starts to cool.
60°N
The warm air rises at
60°N. Temperate Low
Atmospheric Circulation Ferrel Cell
Polar
Cell
90N°
30S°
Ferrel
Hadley
Hadley
Cell
Cell
Cell
60N°
30N°
0°
Rising
warm
coolair
airair
from
from
Hadley
CellCell
Air dragged byDescending
both
Cells
causes
to Polar
circulate,
Ferrel Cell,
pulls
down
upthe
more
air equator
with
air it.
with
and distributedrags
heat
from
to it
the poles.
Atmospheric Circulation Winds
The next slide shows how winds move across the
surface of the earth.
A Key Principle is that these winds move from
areas of high pressure to low pressure.
Complete the diagram showing surface
winds in your workbook.
PC
90N°
60N°
FC
30N°
HC
0°
30S°
60S°
90S°
90N
°
Air falling at the Polar
High Pressure (90°N)
Falling
air at
move
towards
thethe
60N Temperate
Sub Tropical
High
Low Pressure
°
Pressure
(60°N)
called(30°N)
Polar
moves
the
Fallingtowards
air at the
Easterlies.
Temperate
Low
Tropical
High
The
Where
last air
winds
rises
we
30N Sub
(60°S)
Pressure
(30°N)
atreally
the Equatorial
need to
°
called
Westerlies.
also
moves
know
Low
are
Pressure
called
towards
the
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South
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East
light
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Low
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called
which
the
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called
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North
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30S East
Trade
Winds.
at 30°S.
°
60S
°
90S
°
Ocean Currents - Global Transfer Of Energy
Ocean currents like Cells and wind
redistribute energy. Heat is taken
from the tropics and moved
towards the pole & vice versa.
For the exam you will have to describe the
movement of these currents and be able to
explain why they move in the way that they do.
Description of Ocean Currents
• Help redistribute energy from areas of surplus to
deficit.
• Account for 20% of energy redistribution.
• Warm currents flow from Equator to Poles.
• Cold currents flow from Poles to Equator.
• Warm currents – Gulf Stream, North Atlantic
Drift.
• Cold currents – Canary, Labrador
• Move in large circular loops called gyres.
• Clockwise in the Northern Hemisphere.
• Anticlockwise in the Southern Hemisphere.
Factors influencing the flow of Ocean Currents
• Winds – currents follow prevailing winds.
• Land Masses – block and deflect currents and
send them off in other directions.
• Corioilis Force - deflects currents to the right in
the northern hemisphere and the left in the
southern hemisphere.
• Salinity(salt) differences in water – flow from
low to high salinity – equator – sub-tropics.
• Uneven heating of water – cold polar water sinks,
flows towards equator and displaces upwards the
warmer water setting up gyres.
Colour this line red,
Colour
it this line in blue, it is
is the warm Gulfthe cold Labrador current.
Stream
Colour this line blue, it is
the cold Canaries Current
Colour this line red it is the
warm Equatorial Current
Ocean Currents Description
These currents
form in warm
equatorial
areas and cold
polar areas.
In the South
the currents
flow in an
anticlockwis
e direction.
The currents
of the oceans
circulate in
large loops
called gyres.
In the North
the currents
flow in a
clockwise
direction.
Ocean Currents Description
In the North Atlantic Gyre
a warm
A cold
current
current
from
from
the
equator
Northern
heads
Canada,
towards
calledthe
the
Labrador
Caribbean,
current
the North
joins the
Equatorial
Gulf Stream
Current.
coolingIt
it then
down.
moves
The current
in a North
starts
Easterly
to flow
south
direction
downtowards
the African
Europe,
coast
as
tothe
theGulf
equator,
Stream
theCurrent.
Canaries
Current, but by now is much
cooler. The cycle then starts
to repeat itself.
Ocean Currents Description
The distribution of heat can
Theof
current
thencurrent
turns
Some
the warm
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in a figure
of
Easterly
towards
South
from the
equator,
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8 pattern
as the
two gyres
Africa and
flows up its
Equatorial
the
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the
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to flowRemember
South West
to the
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Current.
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questions
you
to warm
up must
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asmention
it it
moves
Current,
cooling
as
that
warm
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spreads
up the travels
African
coast
where it
South.
heat rejoins
pole wards
the
cool
the and
warm
South
water
helps cool
the
Equatorial
Current.
equatorial regions.
Ocean Currents Explanation
When explaining how these
currents circulate there
areTask
4 key
tosplit
make
For
14points
you will
as well
as one
explaining
into
groups
to find
out
temperature
about
these keychnages;
points,
reporting back to each
1. Wind
other what you find.
2. Coriolis effect
3. Position Of Continents
4. Convection Currents
5. You also need to know why
the currents warm or cool
Ocean Currents Explanation
Prevailing Winds
Westerlies
North East
Trade Winds
The Trade winds and the
Westerlies drive the ocean
currents in a clockwise
direction a result of falling
& rotating air at the sub
tropics (30ºN). The
equatorial current is picked
up by the North East trade
winds & sent to the
caribbean, the rotation
then continues so that the
Westerlies send the
current to the North East.
Ocean Currents Explanation
Coriolis Effect
This is the West to
East rotation of the
earth that drives the
ocean currents the
northern hemisphere in
a clockwise direction
Ocean Currents Explanation
North America
Europe
The continents
deflect currents
into a clockwise
movement
Africa
Ocean Currents Explanation
More insolation
received at the
equator than
the poles
results in
convection
currents. Warm
currents rise at
the equator and
then drop back
down into the
sea at higher
latitudes,
helping to mix
warm and cold
currents.
Ocean Currents Explanation
Explaining distribution of cold and
warm temperature by currents.
You also have to state the obvious!
As warm currents move northwards from the
equator, they distribute heat to the cooler high
latitudes nearer the poles.
At the same time, movement of cold currents from
the poles to lower latitudes helps to distribute cool
temperatures to the warm equatorial areas.
Changes In Global Temperatures
Diagram Showing Global Temperature Variations 1850 -2000
-0.8
This Trend
-0.6
Fluctuates Upwards
+0.4
+0.2
1951-1990
Average
Global
Temperature
0°C
-0.2
-0.4
-0.6
1850
1875
1900
1925
1950
1975
2000
Global Mean Temperatures
Have Risen
Changes In Global Temperatures
Diagram Showing Global Temperature Variations 1850 -2000
Highest Value 0.4°C
+0.8
+0.6
Temperature Range 0.82
°C
+0.4
+0.2
1951-1990
Average
Global
Temperature
0°C
-0.2
-0.4
-0.6
1850
1875
1900
1925
Lowest value -0.42°C
1950
1975
2000
Changes In Global Temperatures
Diagram Showing Global Temperature Variations 1850 -2000
-0.8
-0.6
+0.4
+0.2
1951-1990
Average
Global
Temperature
0°C
-0.2
-0.4
-0.6
1850
1875
1900
1925
1950
1975
2000
Rapidly
Increasing
-0.2
to -0.1°C below Average
-0.4 to – 0.3°C Below Average
Temperature
Above 1920 - 1975
Temperature
Temperature 1850 - 1920
Average 1975 - 2000
Changes In Global Temperatures
The overall trend is that the Global mean temperature has
fallen/stabilised/risen between 1850 & 2000, in a steady/fluctuating
manner against the 1951–1990 average/long term average. The
lowest value was -0.42/-0.38 °C and the highest +0.4 °C giving a
range of -0.2/+0.2/0.78/0.82 °C around the mean for 1950. There
was a period with below average temperatures of around -0.4°C to
-0.3°C between 1850 & 1920/1850 & 1950/1940 & 2000. There was
a period of gentle increase between -0.2°C & -0.1°C below the
1950 average from 1920 & 1940/1920 & 1975. A period of
slow/moderate/rapid increase above the 1950 mean took place
between 1940 & 2000/1975 & 2000.
Changes In Global Temperatures
Physical Factors
Sunspot activity sends more
insolation to the earth
Dust from
volcanoes
reflects away
insolation
Changes In Global Temperatures
Physical Factors
If the earth’s orbit
changes we can be
further from the sun
and start to cool.
Changes In Global Temperatures
Physical Factors
If the earth tilts away
from the sun the
Northern Hemisphere
will cool
Changes In Global Temperatures
Human Factors
CO2 absorbs heat and
reradiates heating up
the earth.
Deforestation adds
CO2 when trees
burnt and less CO2
converted into water
by trees.
Methane, Nitrous
Oxides & CFC
emissions do the same
as CO2.
Inter Tropical Convergence Zone (ITCZ)
This is simply the area between the two Tropics
(Cancer & Capricorn) where two different air masses
meet. As it is a low pressure area/belt there is rain.
This is a result of the high levels of insolation at the
equator causing the movement of warm air upwards.
First try and work out a few definitions
for Task 16, use your knowledge of the
English language & your teacher to help.
Inter Tropical Convergence Zone (ITCZ)
Inter Tropical
Convergence
Zone
between the tropics
of Cancer & Capricorn.
where two or more
things meets in this
case air masses
an area
Task 16
?
ITCZ
ITCZ
• The migration of the inter-tropical convergence
zone (ITCZ) in Africa affects seasonal rainfall
patterns across the continent.
• It is an area of low pressure that forms where the
Trade Winds meet near the earth's equator.
• As these winds converge, moist air is forced
upward. As it rises, the air cools, resulting in a
band of heavy rain around the globe.
• This band moves seasonally, due to the changing
position of the overhead sun.
Position of the ITCZ: January
Tropic
of Cancer
Equator
Tropic
of Capricorn
Task 17 ITCZ Air Masses
Tropical
Continental (cT)
Dry
Air masses = ?
Tropical climate = ? & why
Maritime climate = ? & why
Continental climate = ? & why
When describing air masses you
must say;
Where they develop
Where they move to
How stable they are
Tropical
Maritime (mT)
Wet
Their temperature & moisture
characteristics
What the weather will be like
Task 18 ITCZ January
Tropical
Continental Dry
Rain as sun & ITCZ
located over Tropic of
Capricorn
Dry area north of ITCZ as
Continental air is dry and
stable, from Sahara Desert
ITCZ
Tropical
Maritime Wet
Task 18 ITCZ March
Tropical
Continental Dry
Rain around equator as
ITCZ located by it
Wet area south of ITCZ as
Maritime air is wet and
unstable
Tropical
Maritime Wet
Dry area north of ITCZ as
Continental air is dry and
stable
Task 18 ITCZ July
Tropical
Continental Dry
Rain as sun and ITCZ
located over Tropic of
Cancer
ITCZ
Wet area just south of
ITCZ as Maritime air is wet
and unstable
Tropical
Maritime Wet
Some convectional rainfall
between 5º N & S of the
equator.
Task 18 ITCZ September
Tropical
Continental Dry
Rain around equator as
ITCZ located by it
Wet area south of ITCZ as
Maritime air is wet and
unstable
Tropical
Maritime Wet
Dry area north of ITCZ as
Continental air is dry and
stable
January
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
March
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
July
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
September
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
January
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
March
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
July
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
September
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn
January
Tropic of
Cancer
I
T
C
Z
Equator
Tropic of
Capricorn