© Oxford University Press 2009 Quit Part 7 Global warmingAre humans responsible? 7.2What is the normal global distribution global distribution pattern.

© Oxford University Press 2009 Quit

Part 7 Global warming─Are humans responsible?

7.27.2 What is the normal What is the normal global distributionglobal distribution pattern of pattern of temperature?temperature?

Part BPart B



Earth’s surface Heated earth’s surface

Insolation

Radiation

Long wave

radiation

Conduction Convection

How is insolation related to the global distribution of temperature?How is energy transferred into the atmosphere?

When the earth’s surface is heated up, it releases heat energy and warms the air

above through three ways.



When is the insolation the highest?When is the insolation the highest?When does the ground receive no

insolation?When does the ground receive no

insolation?

What is the relationship between insolation and air temperature?

The more the insolation, the ( higher / lower ) the air temperature.Air temperature is controlled by __________.insolation

At noon.Between

sunset and sunrise.

Maximum insolation

No insolation

No insolation



Around 16-17°C

Around 27-28°C

What is the world distribution pattern of temperatures? What is the July

temperature of London and Hong Kong?

What is the July temperature of London

and Hong Kong?

What is the January temperature of London

and Hong Kong?

What is the January temperature of London

and Hong Kong?

Around 3°C

20°C

( Hong Kong / London ) has a higher temperature in both July and January.



What is the world distribution pattern of temperatures?

( Low- / Mid- ) latitude region

( Low- / Mid- ) latitude

region

What regions are London and Hong Kong located at?

What regions are London and Hong Kong located at?

What conclusion can you draw from

this?

What conclusion can you draw from

this?

Temperature ( decreases / increases ) with increasing latitude.Temperature is ( lower / higher ) in lower-latitude regions.

1 Air temperature is higher in low-latitude regions



2 Temperature variation over latitude is more marked in winter in the Northern Hemisphere

The ( Northern / Southern ) Hemisphere has a closely-

spaced pattern of isotherms in January.

It means temperature variation over latitude

is more marked in winter in the Northern

Hemisphere.



2 Temperature variation over latitude is more marked in winter in the Northern Hemisphere

JanuaryJuly

Moscow: ____°CJerusalem: ____°CDifference: ____°C

152914

Moscow: ____°CJerusalem: ____°CDifference: ____°C

-151530

Let’s look at the temperatures of Moscow and Jerusalem.

The two cities have a larger temperature difference in

( summer / winter ).



July

What are the temperatures of Places A and B which are at the same

latitude?

What are the temperatures of Places A and B which are at the same

latitude?

Place A: ____°CPlace B: ____°C

Difference: ____°C

8124 January

Place A: ____°CPlace B: ____°C

Difference: ____°C

0-3434

3 Places at the same latitude may have different air temperatures

What conclusion can you draw from this?



January

3 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?

The isotherms in mid-latitudes in the Southern Hemisphere are roughly

parallel to the latitudes. Why?

It is because most of the area there is covered by sea. The changes in

temperature are relatively ( small / large ).



4 There is a seasonal pattern of air temperature

0

July

Compare the difference of temperatures of

Tokyo and Sydney in July and January

respectively.

Temperature in July (°C)

Tokyo

Sydney

Temperature in January (°C)

24

13

January

0°

8

21

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.

25

20

15

10

5



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

Winds Ocean currents

Aspect Altitude Cloud cover







How is insolation related to the global distribution of temperature?What are the factors affecting temperature patterns?

Land and sea

Winds Ocean currents

Aspect Altitude Cloud cover

Factors affecting temperature patterns

Insolation The more the insolation received, the ( lower /

higher ) the air temperature.



2 Land and seaJuly

January

Moscow:15°C

Place A (over the sea): 8°C

Place A (over the sea): -6°C

Moscow: -15°C

A

A

Why are there different

temperatures at places at the same latitude?

Why are there different

temperatures at places at the same latitude?

In July, Moscow is ( colder / hotter ) than Place A.In January, Moscow is ( colder / hotter ) than Place A.



2 Land and sea

8°CLand absorbs heat more quickly

15°C

Sea loses heat more slowly

-6°CLand loses heat more quickly

-15°C

Heat can be transferred quickly through the land by __________. Hence, the land absorbs and loses heat quickly.

The water in oceans is heated by __________. As oceans are large bodies of water, it takes time to transfer the heat. Hence, oceans absorb and lose heat slowly.

conduction

convection

Sea absorbs heat more slowly

Place A

Place A



2 Land and sea Annual range of temperatureCopenhagen: 18°CMoscow: 30°C

( Copenhagen / Moscow ) has a smaller annual range of temperature.

Copenhagen is located at the coast. _______ help regulate the temperature along coastal areas.

Oceans

Maritime climate:Mild winters and cool summers

Continental climate:Cold winters and hot / warm summers



2 Land and sea

Annual range of temperature

What characteristics do you notice about the distribution of annual range of temperature?

What characteristics do you notice about the distribution of annual range of temperature?

Annual range of temperature( decreases / increases ) as the latitude increases;( decreases / increases ) with the distance from the sea.



How do winds affect the

temperature of a place?

How do winds affect the

temperature of a place?

3 WindsThis is the seasonal pattern of winds in Hong Kong:

Hong Kong

Winter

Hong Kong

Cold northerly winds blowing from the cold inland areas of the mainland

Some places receive onshore winds in winter. The warm onshore winds from the sea help raise the winter temperature there.

South-easterly winds blowing from the Pacific Ocean

Summer

Temperature in Hong Kong (

/ )

Temperature in Hong Kong (

/ )



4 Ocean currentsOcean 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



4 Ocean currents

How do ocean currents affect the

temperatures of the places lying along

their paths?

How do ocean currents affect the

temperatures of the places lying along

their paths?

Warm ocean currents originate from areas where the water is warm.

Warm ocean currents originate from areas where the water is warm.

The air above the currents becomes ( cold / warm ).

The air above the currents becomes ( cold / warm ).

Places lying along the paths of warm ocean

currents have ( lower / higher ) temperatures.

Places lying along the paths of warm ocean

currents have ( lower / higher ) temperatures.



4 Ocean currents Cold ocean currents originate from areas where the water is cold.

Cold ocean currents originate from areas where the water is cold.The air above

the currents becomes cold.

The air above the currents

becomes cold.

Places lying along the paths of cold ocean currents have

lower temperatures.

Places lying along the paths of cold ocean currents have

lower temperatures.



4 Ocean currents

Glasgow Nain

Located at similar latitudes, both Glasgow and Nain are affected by

ocean currents.

What do you notice about the relationship between the type of ocean current and mean temperatures in

July and January of Glasgow and Nain?

What do you notice about the relationship between the type of ocean current and mean temperatures in

July and January of Glasgow and Nain?

Ocean currentMean temperature

in JulyMean temperature

in January

Glasgow

Nain

North Atlantic Drift

( cold / warm ) current

Labrador Current

( cold / warm ) current

17°C

( lower / higher ) temperature

8.2°C


5°C


-21.7°C




5 AspectAspect refers to the direction a slope faces in relation to the sun.

Sun’s rays strike at a larger angle on south-facing slopes

Sun’s rays strike at a smaller angle on north-facing slopes

South-facing slopes receive ( less / more ) insolation per unit area

North-facing slopes receive less insolation per unit area

Northern Hemisphere What is the situation in

the Southern Hemisphere? What is the situation in

the Southern Hemisphere?



6 Altitude

Denser air

Heat loss

_____________, ______ and _______________ in the atmosphere absorb long wave radiation and keep the air warm

Water vapour dustcarbon dioxide

Less dense air

Heat released from the earth’s surface is stored in the air

Heat loss

Less dense air absorbs ( less / more ) heat

Air becomes less dense with increasing altitude. Heat loss is faster and thus the air temperature ( falls / rises ).

The average rate of decrease in air temperature with height is 6°C per 1,000

metres. This is known as the ________________________.environmental lapse rate



7 Cloud cover

Earth’s surface Earth’s surface

With cloud cover Without cloud cover

Insolation

Direct reflection

Place A Place B

Daytime

A large part of the insolation reaches the

earth’s surface

Only part of the insolation reaches the

earth’s surface

Which area would have a lower temperature?

Which area would have a lower temperature?

Insolation



7 Cloud cover

Night time

Which area has a larger daily range of temperature?

Which area has a larger daily range of temperature?

Earth’s surface Earth’s surface

With cloud cover Without cloud cover

The warmth is kept

The warmth is lost

Only a small part of the radiation is released back to space

A large part of the radiation is blocked by the clouds

A large part of the radiation would be

released back to space

Place A Place B

Longwave radiation

Longwave radiation

Some radiation is absorbed by clouds

© Oxford University Press 2009 Quit Part 7 Global warmingAre humans responsible? 7.2What is the normal global distribution global distribution pattern.

Documents

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