Global warming─Are humans responsible?
Part 7
7.2
© Oxford University Press 2009
What is the normal
global distribution
pattern of
temperature?
Part B
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How is insolation related to the global
distribution of temperature?
How is energy transferred into
the atmosphere?
Radiation
When the earth’s surface is
heated up, it releases heat
energy and warms the air above
through three ways.
Conduction
Convection
Long
wave
radiation
Insolation
Heated
Earth’s
earth’s
surface
surface
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What is the relationship between insolation
and air temperature?
When
does
the ground
receive
no
Air
is
controlled
by
__________.
Thetemperature
more
the
insolation,
the
(
higher
/
lower ) the
insolation
When is the insolation the highest?
air temperature. insolation?
Between
sunset
At noon.
and
sunrise.
Maximum
insolation
No
insolation
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No
insolation
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What is the world distribution pattern of
temperatures?
What
is the
January
What
is the
July
temperature
temperature of
of London
London
and
and Hong
Hong Kong?
Kong?
Around
Around
16-17°C
3°C
© Oxford University Press 2009
Around
20°C
27-28°C
( Hong Kong /
London ) has a
higher
temperature in
both July and
January.
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What is the world distribution pattern of
temperatures?
What regions
conclusion
What
are
1
Air temperature is higher
in
can
youlow-latitude
draw
from
London
and Hong
this? at?
regions
Kong located
( Low- / Mid- )
latitude region
© Oxford University Press 2009
( Low- / Mid- )
latitude region
Temperature
( decreases /
increases ) with
increasing latitude.
Temperature is
( lower / higher )
in lower-latitude
regions.
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Temperature variation over latitude is
more marked in winter in the Northern
Hemisphere
It means temperature
variation over latitude
is more marked in
winter in the Northern
Hemisphere.
© Oxford University Press 2009
The ( Northern / Southern )
Hemisphere has a closelyspaced pattern of isotherms
in January.
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Temperature variation over latitude is
more marked in winter in the Northern
The two cities have a larger
Hemisphere
Let’s look at the temperatures of
temperature difference in
Moscow and Jerusalem.
( summer / winter ).
© Oxford University Press 2009
July
January
Moscow: ____°C
15
Jerusalem: ____°C
29
Difference: ____°C
14
Moscow: ____°C
-15
Jerusalem: ____°C
15
Difference: ____°C
30
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Places at the same latitude may have
different air temperatures
What are the temperatures of Places A
conclusion
you
draw from this?
and BWhat
which
are at thecan
same
latitude?
8
Place Place
A: ____°C
0 A: ____°C
12
Place Place
B: ____°C
-34B: ____°C
Difference:
4
Difference:
____°C
34 ____°C
July
January
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Places at the same latitude may have
different air temperatures
July
The isotherms in mid-latitudes in the
Southern Hemisphere are roughly
parallel to the latitudes. Why?
January
It is because most of the area there is covered
by sea. The changes in temperature are
relatively ( small / large ).
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There is a seasonal pattern of air
temperature
Temperature in Temperature in
Compare
January (°C)
July (°C) the difference
of temperatures of
24
8
Tokyo and Sydney in
Sydney
13 and January
21
July
respectively.
In July, it is ( summer / winter )
in the Northern Hemisphere and
( summer / winter ) in the
Southern Hemisphere.
In January, it is winter in the
Northern Hemisphere and summer
in the Southern Hemisphere.
Tokyo
0°
0
25
20
15
January
July
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10
5
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How is insolation related to the global
distribution of temperature?
What are the factors affecting temperature
patterns?
Factors affecting temperature patterns
Insolation
Land and
sea
Aspect
© Oxford University Press 2009
Altitude
Winds
Ocean
currents
Cloud cover
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Global warming─Are humans responsible?
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Part 7
© Oxford University Press 2009
Global warming─Are humans responsible?
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Global warming─Are humans responsible?
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How is insolation related to the global
distribution of temperature?
What are the factors affecting temperature
patterns?
Factors affecting temperature patterns
Insolation
Land
and the insolation
Winds
The more
sea the ( lower / higher )
received,
the air temperature.
Aspect
© Oxford University Press 2009
Altitude
Ocean
currents
Cloud cover
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Land and sea
July

Moscow:
15°C
A

Place A (over the
sea): 8°C
January

Moscow:
-15°C
Why are there
different
temperatures
at places at the
same latitude?
A

Place A (over the
sea): -6°C
In July, Moscow is ( colder / hotter ) than Place A.
In January, Moscow is ( colder / hotter ) than Place A.
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Land and sea
15°C
Place A
8°C
Land absorbs
heat more quickly
Sea absorbs heat
more slowly
-15°C
Place A
Land loses heat
more quickly
© Oxford University Press 2009
-6°C
Sea loses heat
more slowly
Heat can be
transferred quickly
through the land by
__________.
conduction Hence,
the land absorbs
and loses heat
quickly.
The water in
oceans is heated
by __________.
convection As
oceans are large
bodies of water, it
takes time to
transfer the heat.
Hence, oceans
absorb and lose
heat slowly.
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Land and sea
Continental climate:
Cold winters and hot /
warm summers
Annual range of temperature
Copenhagen: 18°C
Moscow: 30°C
Maritime climate:
Mild winters and
cool summers
( Copenhagen / Moscow ) has a smaller annual range of
temperature.
Copenhagen is located at the coast. _______
Oceans help
regulate the temperature along coastal areas.
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Land and sea
What characteristics
do you notice about
the distribution of
annual range of
temperature?
Annual range of temperature
Annual range of temperature
( decreases / increases ) as the latitude increases;
( decreases / increases ) with the distance from
the sea.
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Winds
This is the seasonal pattern of winds in Hong Kong:
Summer
Winter
How do winds
Cold northerly
Temperature in
affect the
winds blowing from
Hong Kong
the cold inland
temperature
of
(
/
)
areas of the
a place?
mainland
Hong Kong
South-easterly winds
blowing from the
Pacific Ocean
Hong Kong
Temperature in
Hong Kong
(
/
)
Some places receive onshore winds in winter. The warm
onshore winds from the sea help raise the winter
temperature there.
© Oxford University Press 2009
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Ocean currents
Ocean currents are seawater flowing along fixed routes.
They are divided into warm currents and cold currents.
Warm currents
flow from
equatorial
areas to polar
areas
Cold currents flow
from polar areas to
equatorial areas
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Ocean currents
Warm ocean
currents originate
from areas where
the water is warm.
How do ocean
affect
Thecurrents
air above
the the
temperatures
of the
currents
becomes
places
lying along
( cold
/ warm
).
their paths?
Places lying along the
paths of warm ocean
currents have ( lower /
higher ) temperatures.
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Ocean currents
The air above
the currents
becomes cold.
Cold ocean
currents originate
from areas where
the water is cold.
Places lying along the paths
of cold ocean currents have
lower temperatures.
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Ocean currents
Nain
Glasgow
Mean temperature
Ocean currentWhat do you notice
in July
Glasgow
Nain
Mean temperature
about
the relationship betweenin January
at similar
17°C of ocean
5°C
North Atlantic Drift
the Located
type
current
latitudes,
both
Glasgow
( lowertemperatures
/ higher
)
( lower
( cold / warm )and
mean
in / higher )
temperature
temperature
current
and
Nain
are
affected
July and January ofby
8.2°C
-21.7°C
Labrador Current
ocean currents.
Glasgow
and Nain?
( cold / warm )
current
© Oxford University Press 2009
( lower / higher )
temperature
( lower / higher )
temperature
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Aspect
Aspect refers to the direction a slope faces in relation to
the sun.
What is the situation in
Northern Hemisphere the Southern Hemisphere?
North-facing slopes
receive less insolation
per unit area
Sun’s rays strike at a
smaller angle on
north-facing slopes
Sun’s rays strike at a
larger angle on southfacing slopes
South-facing slopes
receive ( less /
more ) insolation
per unit area
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Altitude
Less dense air
Denser air
Air becomes less dense with increasing
altitude. Heat loss is faster and thus the air
temperature ( falls / rises ).
Heat
The average rate of
decrease
loss
in air temperature with height
Less dense
air
is 6°C per 1,000 metres.
This
( less
is known asabsorbs
the
/ more ) heat
________________________.
environmental lapse rate
Heat released from the earth’s
surface is stored in the air
_____________,
Water vapour ______
dust
and _______________
carbon dioxide in
the atmosphere absorb
long wave radiation and
keep the air warm
© Oxford University Press 2009
Heat
loss
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Cloud cover
Daytime
Which area would
have a lower
temperature?
Insolation
Insolation
Direct
reflection
With cloud cover
Only part of the
insolation reaches the
earth’s surface
Place A
Without cloud cover
A large part of the
insolation reaches the
earth’s surface
Place B
Earth’s surface
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Earth’s surface
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Which area has a
larger daily range
of temperature?
Cloud cover
Night time
Only a small part
of the radiation
is released back
to space
With cloud cover
The
warmth
is kept
Some
radiation is
absorbed
by clouds
Longwave
radiation A large part of
the radiation is
blocked by the
clouds
Place A
Earth’s surface
© Oxford University Press 2009
Without cloud cover
A large part of the
radiation would be
released back to space
The warmth
is lost
Place B
Longwave
radiation
Earth’s surface
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