Global warming─Are humans responsible?
Part 7
7.2
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What is the normal
global distribution
pattern of
temperature?
Part A
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Part 7
Global warming─Are humans responsible?
What is the major factor affecting air
Monthly mean temperatures
temperature?
What is the relationship
between location and
annual mean
temperature of the
Insolation.
following three places?
What makes the air
temperature vary among
latitudes and at different
times of a year?
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Global warming─Are humans responsible?
Part 7
What is insolation?
The sun is
constantly
releasing energy
Solar
in all directions.
radiation
In order to have a better
This energy is
understanding of the issue
of as solar
known
global warming, we have
to
radiation.
know more about insolation.
Space
The atmosphere
Insolation
Solar radiation that is
received in the
atmosphere or on the
earth’s surface is
known as insolation.
Earth’s surface
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Global warming─Are humans responsible?
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What is insolation?
Is insolation evenly distributed on the earth?
Less insolation
More insolation
+
Average annual insolation over the earth’s surface
In
general,
insolation
receivedon
( declines
increases )
The
distribution
of insolation
the earth’s/ surface
with
increasing
latitude.
is ( even
/ uneven
).
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Global warming─Are humans responsible?
Part 7
What is insolation?
Is insolation evenly distributed on the earth?
Why does
insolation vary
with latitudes?
Average annual insolation over the earth’s surface
The
areas
around
_______
N and value
S receive
the highest
Which
areas
receive
the highest
of insolation?
value of insolation.
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Global warming─Are humans responsible?
Part 7
What is insolation?
What factors affect insolation received on
the earth’s surface?
Factors affecting insolation
received on the earth’s surface
Angle of the
sun
Latitude
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Duration of
daylight
Time of a
day
The
atmosphere
Season
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Global warming─Are humans responsible?
Part 7
In Part B, we will discuss the
relationship between insolation
and air temperature.
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Part 7
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Global warming─Are humans responsible?
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Global warming─Are humans responsible?
Part 7
1
Angle of the sun
The angle of the sun refers
to the angle at which
sunlight strikes the earth’s
surface.
When the sun is directly
overhead, or when the angle
of the sun is 90°, it is known
as the overhead sun.
Overhead sun
Area A
90° angle
/ Right of
angle
Angle of the
sun
How
does the
the
the
Area to warm
upsun affect
Smaller
intensity of insolation?
Intensity of
insolation
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High / More intense
Area B
< 90° / Acute angle
Larger
Low / Less intense
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Angle of the sun
A
Latitude
In low-latitude regions:
The angle of sun is
( smaller / larger ).
The insolation concentrates
on a ( smaller / larger )
area.
Therefore, the insolation is
( weaker / stronger ).
(Credit: NASA)
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Angle of the sun
A
Latitude
In high-latitude regions:
The angle of sun is
( smaller / larger ).
The insolation concentrates
on a ( smaller / larger )
area.
Therefore, the insolation is
( weaker / stronger ).
(Credit: NASA)
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Angle of the sun
B
Time of a day
The sun at noon
is called the
midday sun
The
amount
The
angle
of sunof
insolation
received
( decreases
/
increases
/ in
will
be lower
reacheswinter.
maximum )
How is the amount of
insolation received in this
site different in winter?
The angle of sun
( decreases /
increases /
reaches maximum )
The angle of sun
( decreases /
increases /
reaches maximum )
The amount of insolation received in a mid-latitude site in the
Northern Hemisphere around the spring equinox
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Angle of the sun
C
Season
What is the
relationship
In spring
summer
autumnal
winter
solstice,
equinox,
solstice,
equinox,
the
the
between
the
the overhead
overhead
sunin
sun
is is
seasons
NS
located
atKong
_______
the
_________.
Equator.
Hong
which
_________.
It
Hong
is the
Kong
isand
time
close
Hong
receives
that
to
Equator
insolation?
Kong
(Hong
more
Kong.
receives
Kong
/ less
receives
It is
less
) the
time( that
the
insolation
leastHong
in/ spring
autumn
largest
Kong )
receives
amount
than
in winter.
summer.
of
the
insolation.
( least /
largest ) amount of
insolation.
Please click above for animation
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Duration of daylight
Is the case in
The duration
longer the
ofduration
daylight of
in daylight,
equatorial
the
regions
( less
is/ almost
more )
polar
areas
12
insolation
hours daily
received.
throughout a year.
different?
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Duration of daylight
While in winter,
In polar regions,
there is no
When
does
the
North
Pole
receive
daylight can last for 24
sunlight at all.
the
largest
amount
of
insolation?
hours in summer.
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The atmosphere
The dust
particles,
molecules
andreaches
clouds in
Only
about
58 unitsgas
of solar
radiation
thethe
earth’s
atmosphere are able to reflect, absorb or scatter solar
surface.
radiation.
How does the
atmosphere affect
the amount of solar
radiation reaching
the earth’s surface?
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The atmosphere
Why does the maximum insolation
received occur at around
N
and S but not at the Equator?
Maximum
insolation
received
Maximum
insolation
received
Maximum
insolation
received
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The climate is drier and there
is less cloud cover at around
N and
S. The earth’s
surface receives more
insolation, so the amount of
insolation is greatest here.
The atmosphere
Space
The atmosphere
Less
cloud
cover
Insolation is
reflected by
clouds
Dense cloud cover
The amount of cloud cover in the equatorial
regions is high. Much of the solar radiation is
reflected by clouds. This may reduce the amount
of insolation reaching the earth’s surface.
S
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0°
Less
cloud
cover
N
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