Presentation on theme: "Sandstorm in China Issue on Weather & Climate. A news extract (18/3/2002) Sandy winds swept Beijing this weekend for the first time this year, forcing."— Presentation transcript:
A news extract (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)
Areas affected by sandstorms Mongolia Gansu Xinjiang
What is the hazard? It is sandstorm/dust storm. Tonnes of sands are blown away by strong winds.
Favourable climatic elements for the occurrence of sandstorms 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 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.
Formation of sandstorm 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
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