tornado英语介绍

A tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud or, in rare cases, a cumulus cloud base and the surface of the earth. Tornadoes come in many sizes but are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris.Most tornadoes have wind speeds between 40 mph (64 km/h) and 110 mph (177 km/h), are approximately 250 feet (75 m) across, and travel a few miles (several kilometers) before dissipating. Some attain wind speeds of more than 300 mph (480 km/h), stretch more than a mile (1.6 km) across, and stay on the ground for dozens of miles (more than 100 km).[1][2][3]Although tornadoes have been observed on every continent except Antarctica, most occur in the United States.[4] They also commonly occur in southern Canada, south-central and eastern Asia, east-central South America, Southern Africa, northwestern and southeast Europe, Italy, western and southeastern Australia, and New Zealand.[5] 飘过~6203124222

The tornado is a 涡旋 ： dragon air around the shaft to rotate rapidly, by a tornado center pressure was reduced to attract, dozens of a thin layer of air currents from all sides, by inhalation 涡旋 bottom. and then into the vortex of 轴心, the strong wind always cyclones, the centre of pressure around 10% lower than the pressure.The atmosphere of instability have a strong rising air currents, the current in the flow of traffic, it was further strengthenedIn a vertical, horizontal with the speed and direction are never get wind of interaction, rising air currents in the troposphere central began to revolve, forming scale necessitatedWith the scale necessitated to the development and progress, itself became fine and strengthened. meanwhile, a small area of increased support to that of the dragon born in the form, cyclones necessitated the same process and the formation of a tornado coreA tornado's whirling core and cyclones in, it was strong enough to make a tornado to the ground. when development reached the surface pressure, the ground with a sharp rise to form strom