Transcript Sandstorm in China - Cheung Chuk Shan College

Sandstorm in China
Issue on Weather & Climate
A news extract
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(18/3/2002) Sandy winds swept Beijing this weekend
for the first time this year, forcing residents who
hoped to enjoy warm spring weather to cut their plans
short.
Winds with forces of 5 to 6 on the Beaufort scale
were wrapped in dust and dominated the sky in
China's capital from late Friday until Sunday.
Meteorologists said it would end today.
Questions to think about:
Identify the climatic hazard. (1)
 Explain how the climatic elements favour the
occurrence of this kind of hazard in winter. (6)
 Account for the formation of the hazard. (5)
 Describe the effects brought by the hazard. (4)
 Suggest some measures to minimize the
negative impacts brought by the hazard. (3)
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Areas affected by sandstorms
Xinjiang
Gansu
Mongolia
What is the hazard?
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It is sandstorm/dust
storm.
Tonnes of sands are
blown away by strong
winds.
Favourable climatic elements for the
occurrence of sandstorms
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Strong winds are brought by the intense high
pressure/anticyclone
which is centred at the continental interior of
China/Mongolia
because it is winter in the northern hemisphere
Temperature is lower over land than the sea
Air sinks and high pressure is formed
Winds are out-blowing and strong,
in clockwise directions
Winds are NW, offshore and dry
Another news extract
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Reports from the Beijing Meteorological
Station said the recent sandstorms were
brought by a cold front from Mongolia. It blew
fine sand from the Inner Mongolia
Autonomous Region and Shanxi and Hebei
provinces all the way to Beijing.
A satellite picture
Direction of sandstorm
Formation of sandstorm
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Spreading of desert
Low annual rainfall
High temperature in summer
Deforestation
Poor farming methods
Over-cultivation
Over-grazing in some provinces e.g. Mongolia
Lead to the loss of protective layer
 Soil erosion
Loosen soil blown away by strong winds
Causing sandstorms
Effects of sandstorm
Lower visibility in urban area
 A lot of dust in the air  dusty weather
 Air pollution
 Damage crops
 Economic loss
 Loss of property
 Disrupt transport e.g. air/road transport
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Solutions
Prevention: to set up warning system to
minimize loss
 Precaution: afforestation/plant more trees
 To prevent soil erosion
 Limit grazing over land/limit the no. of herds
(animals kept by the farmers)
 Introduce scientific farming methods
 To prevent the deserts from spreading
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