The tornado, or tornado is the air whirlwind which arose in a storm cloud and extending down to the Earth's surface. The tornado has an appearance of a narrow funnel with a diameter up to one hundred meters. The word "tornado" came from an Old Russian "smjrch" - "cloud".
Instruction
1. The causes of tornadoes are studied insufficiently. Emergence factors for typical tornadoes are revealed. The tornado can appear at contact of the warm air filled with water vapor with cold dry air which is formed over the cold surfaces of the sea.
2. In the place of contact of warm air with cold there is a transition of water vapor to liquid state to formation of rain drops. At the same time heat heating air is generated. Heated air rises up, at the same time creating a depression zone. Warm damp air of a cloud and cold air of the lower layers begins to come to this zone. There is a considerable allocation of energy. As a result of process the characteristic funnel is formed.
3. In a funnel the air depression as air rises with high speed up is formed. Cold air which it is even stronger cooled comes to a zone of depression. The funnel falls down, to the Earth's surface. In a zone of depression everything that can lift an air flow is involved. The zone of depression moves to that party from where the largest volume of cold air arrives.
4. Destructions in case of a tornado result from local allocation of the energy which is saved up with formation of water vapor. An initial power source is the solar heat.
5. Power of a tornado begins to weaken at reduction of volumes of cold or warm damp air. The funnel is gradually narrowed, then gradually rises up in a maternal cloud.
6. Duration of a tornado fluctuates of several minutes till several o'clock. Speed of the movement of tornadoes also differs. Average speed of a typical tornado – from 40 to 60 km/h. In rare instances the speed of a tornado reaches 480 km/h.
7. Due to the warming the volume of water vapor in the atmosphere over the World Ocean constantly increases. The climate accepts continental type with hot summer, in the frosty winter and a small amount of precipitation more and more. Owing to these reasons the quantity of tornadoes and their power will increase.