______ is a type of fog occurring close to the sea surface when the air is dry and cold-probably at least 9℃ below the sea surface temperature．
A.MIXING FOG
B.ADVECTION FOG
C.RADIATION FOG
D.ARCTIC SEA SMOKE
共用题干 第二篇Hurricane（咫风）KatrinaA hurricane is a fiercely powertul , rotating（旋转的）form of tropical storm that can be 124 to 1,240 miles in diameter. The term hurricane is derived from Hurican,the name of a native American storm god.Hurricanes are typical of a calm central region of low pressure between 12 to 60 miles in diameter,known as the eye.They occur in tropical regions. Over its lifetime,one of these storms can release as much energy as 10,000 nuclear bombs.The seed for hurricane formation is a cluster（聚集）of thunderstorms over warm tropical waters.Hurricanes can only form and be fed when the sea-surface temperature exceeds 27℃ and the surrounding atmosphere is calm.These requirements are metbetween June and November in the northern part of the world.Under these conditions, large quantities of water evaporate（蒸发）and condense（冷凝）into clouds and rain-releasing heat in the process.It is this heat energy,combined with the rotation of the Earth,that drives a hurricane.When the warm column of air from the sea surface first begins to rise,it causes an area of low pressure.This in turn creates wind as air is drawn into the area.This spinning wind drags up more moist air from the sea surface in a process that strengthens the storm.Cold air falls back to the ocean surface through the eye and on the outside of the storm.Initially,when wind speeds reach 23 miles per hour,these mild,wet and grey weather systems are known as depressions,or low air pressure.Hurricane Katrina formed in this way over the south-eastern Bahamas on 23 August 2005.Katrina has had a devastating impact on the Gulf Coast of the US,leaving a disaster zone of 90,000 square miles in its wake（尾迹）一almost the size of the UK. Thousands have been killed or injured and more than half a million people have become homeless in a humanitarian（人道主义的）crisis of a scale not seen in the US since the Great Depression.The cost of the damage may top $100 billion.Which of the following is NOT a"requirement"for the formation of a hurricane?A:Calm surrounding atmosphere.B:High air pressure.C:Warm sea-surface temperature.D:A group of thunderstorms over warm tropical waters.
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单选题What occurs when rising air cools the dew point?（）A advection fog formsB humidity decreaseC wind increaseD Cloud form
单选题When electrical equipment is involved in a fire，the stream of dry chemicals should be（）.A aimed at the source of the flamesB fogged above the equipmentC shot off a flat surface onto the flamesD used to shield against electrical shock
单选题When must a dry chemical fire extinguisher be recharged?（）A After each useB When the air temperature exceeds 90°FC Every 6 monthsD Every 12 months
单选题The type of fog that occurs on clear nights with very light breezes and forms when the earth cools rapidly by radiation is known as（）.A Radiation fogB Frontal fogC Convection fogD Advection fog
单选题The fog most commonly encountered at sea is called（）.A conduction fogB radiation fogC frontal fogD advection fog
单选题Advection fog may be formed by cold air passing over a（）.A colder sea surfaceB warmer sea surfaceC dry coastal plainsD high mountain or plateau
