Climatic Hazards-Causes,Impacts and Response essays

Climatic Hazards-Causes,Impacts and Response essays a) Discuss the atmospheric processes responsible for (i) strong winds (ii) drought. Strong winds are largely caused by differences in pressure over areas of the land. Wind direction is always from low pressure to high pressure as if a high pressure system is dominant over an area the air can only rise and once it has risen the only place for it to move is to a low pressure area. This determines how fast or weak the winds are. The closer the isobars are the quicker the air can move from high to low pressure thus the winds are stronger. Very strong winds can be found around the equator because the intense heating of the land means that the air rises more quickly. Hurricanes form in this area near the Americas. They develop as hot seawater, which can acquire temperatures of 27c or above, heats the air above it. As this air starts to rise it draws moisture up form the sea like a vacuum. An area of intense low pressure is formed in the centre, this is called the eye of the storm and is an area of calm. As air is sucked up to replace the rising air, winds of about 150-200kph initiate. Cumulo nimbus clouds form and torrential rain starts to fall. The sea is a constant form of strength for them as more and more warm moist air is sucked up, this is why as they begin to travel over land they start to die out. Tornadoes are very similar to hurricanes and cyclone (the Asian equivalent of a Hurricane) although they occur on a smaller scale and originate over land, which is why they are less powerful. They are most common in America, especially in an area nicknamed tornado alley, which stretches from Canadas Great Lakes to Texas. The rotation of the Earth creates another force, termed Coriolis force, which acts upon wind and other objects in motion in very predictable ways. According to Newton's first law of motion, air will remain moving in a straight line unless it is influenced by an unbalanc...