Reading Practice
Antarctic
Research
A
A little over a century ago, men of the ilk of Scott,
Shackleton and Mawson battled against Antarctica’s blizzards, cold and
deprivation. In the name of Empire and in an age of heroic deeds they created
an image of Antarctica that was to last well into the 20th century – an image
of remoteness, hardship, bleakness and isolation that was the province of only
the most courageous of men. The image was one of a place removed from everyday
reality, of a place with no apparent value to anyone.
B
As we enter the 21st century, our perception of Antarctica
has changed. Although physically Antarctica is no closer and probably no
warmer, and to spend time there still demands a dedication not seen in ordinary
life, the continent and its surrounding ocean are increasingly seen to an
integral part of Planet Earth, and a key component in the Earth System. Is this
because the world seems a little smaller these days, shrunk by TV and tourism,
or is it because Antarctica really does occupy a central spot on Earth’s
mantle? Scientific research during the past half-century has revealed – and
continues to reveal – that Antarctica’s great mass and low temperature exert a
major influence on climate and ocean circulation, factors which influence the
lives of millions of people all over the globe.
C
Antarctica was not always cold. The slow break-up of the
super-continent Gondwana with the northward movements of Africa, South America,
India and Australia eventually created enough space around Antarctica for the
development of an Antarctic Circumpolar Current (ACC), that flowed from west to
east under the influence of the prevailing westerly winds. Antarctica cooled,
its vegetation perished, glaciation began and the continent took on its
present-day appearance. Today the ice that overlies the bedrock is up to 4km
thick, and surface temperatures as low as – 89.2deg C have been recorded. The
icy blast that howls over the ice cap and out to sea – the so-called katabatic
wind – can reach 300 km/hr, creating fearsome wind-chill effects.
D
Out of this extreme environment come some powerful forces
that reverberate around the world. The Earth’s rotation, coupled to the
generation of cells of low pressure off the Antarctic coast, would allow
Astronauts a view of Antarctica that is as beautiful as it is awesome. Spinning
away to the northeast, the cells grow and deepen, whipping up the Southern
Ocean into the mountainous seas so respected by mariners. Recent work is
showing that the temperature of the ocean may be a better predictor of rainfall
in Australia than is the pressure difference between Darwin and Tahiti – the
Southern Oscillation Index. By receiving more accurate predictions, graziers in
northern Queensland are able to avoid overstocking in years when rainfall will
be poor. Not only does this limit their losses but it prevents serious pasture
degradation that may take decades to repair. CSIRO is developing this as a
prototype forecasting system, but we can confidently predict that as we know
more about the Antarctic and the Southern Ocean we will be able to enhance and
extend our predictive ability.
E
The ocean’s surface temperature results from the interplay
between deep-water temperature, air temperature and ice. Each winter between 4
and 19 million square km of sea ice form, locking up huge quantities of heat
close to the continent. Only now can we start to unravel the influence of sea
ice on the weather that is experienced in southern Australia. But in another
way, the extent of sea ice extends its influence far beyond Antarctica. Antarctic
krill – the small shrimp-like crustaceans that are the staple diet for baleen
whales, penguins, some seals, flighted sea birds and many fish – breed well in
years when sea ice is extensive and poorly when it is not. Many species of
baleen whales and flighted sea birds migrate between the hemispheres and when
the krill are less abundant they do not thrive.
F
The circulatory system of the world’s oceans is like a huge
conveyor belt, moving water and dissolved minerals and nutrients from one
hemisphere to the other, and from the ocean’s abyssal depths to the surface.
The ACC is the longest current in the world and has the largest flow. Through
it, the deep flows of the Atlantic, Indian and Pacific Oceans are joined to
form part of single global thermohaline circulation. During winter, the howling
katabatics sometimes scour the ice off patches of the sea’s surface leaving
large ice-locked lagoons, or ‘polynyas’. Recent research has shown that as
fresh sea ice forms, it is continuously stripped away by the wind and maybe
blown up to 90km in a single day. Since only freshwater freezes into ice, the
water that remains becomes increasingly salty and dense, sinking until it
spills over the continental shelf. Coldwater carries more oxygen than warm
water, so when it rises, well into the northern hemisphere, it reoxygenates and
revitalises the ocean. The state of the northern oceans and their biological
productivity owe much to what happens in the Antarctic.
Questions 1-5
The reading Passage has seven paragraphs A-F
Which
paragraph contains the following information?
Write the correct letter A-F, in boxes 1-5 on your answer
sheet.
1.....................
The example of research on weather prediction on agriculture
2.....................
Antarctic sea ice brings life back to the world oceans’ vitality.
3.....................
A food chain that influences the animals living pattern based on Antarctic
fresh sea ice
4.....................
The explanation of how atmosphere pressure above Antarctica can impose an
effect on global climate change
5.....................
Antarctica was once thought to be a forgotten and insignificant continent
Question 6-8
Summary
Please
match the natural phenomenon with correct determined factor
Choose the correct answer from the box;
Write the correct letter A-F, in boxes 6-8 on your answer
sheet.
6. Globally,
mass Antarctica’s size and 6.....................
influence climate change
7. 7..................... contributory to
western wind
8. Southern
Oscillation Index based on air pressure can predict 8..................... in Australia
A Antarctic
Circumpolar Current (ACC)
B katabatic
winds
C rainfall
D temperature
E glaciers
F pressure
Questions 9-13
Choose
the correct letter A, B, C or D.
Write your answer in box 22-26 on your answer sheet.
9.
In paragraph B, the author wants to tell which of the following truth about the
Antarctic?
A To
show Antarctica has been a central topic of global warming in Mass media
B To
illustrate its huge sea ice brings food to million lives to places in the world
C To show it
is the heart and its significance to the global climate and currentD To
illustrate it locates in the central spot on Earth geographically
10.
Why do Australian farmers keep an eye on the Antarctic ocean temperature?
A Help
farmers reduce their economic or ecological losses
B Retrieve
grassland decreased in the overgrazing process
C Prevent
animal from dying
D A
cell provides fertilizer for the grassland
11.
What is the final effect of katabatic winds?
A Increase
the moving speed of ocean current
B Increase
salt level near the ocean surface
C Bring
fresh ice into southern oceans
D Pile
up the mountainous ice cap respected by mariners
12.
The break of the continental shelf is due to the
A Salt
and density increase
B Salt
and density decrease
C global
warming resulting in a rising temperatureD fresh ice melting into ocean water
13.
The decrease in the number of Whales and seabirds is due to
A killers
whales are more active around
B Sea
birds are affected by high sea level salty
C less
sea ice reduces the productivity of food source
D seals
fail to reproduce babies
Solution:
|
1. D |
8. C |
|
2. F |
9. C |
|
3. E |
10. A |
|
4. C |
11. C |
|
5. A |
12. C |
|
6. D |
13. C |
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7. A
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