龙卷风用英语介绍

龙卷风是一种涡旋:空气绕龙卷的轴快速旋转,受龙卷中心气压极度减小的吸引,近地面几十米厚的一薄层空气内,气流被从四面八方吸入涡旋的底部。并随即变为绕轴心向上的涡流,龙卷中的风总是气旋性的,其中心的气压可以比周围气压低百分之十。
龙卷风是云层中雷暴的产物。具体的说,龙卷风就是雷暴巨大能量中的一小部分在很小的区域内集中释放的一种形式。龙卷风的形成可以分为四个阶段:
(1)大气的不稳定性产生强烈的上升气流,由于急流中的最大过境气流的影响,它被进一步加强。

(2)由于与在垂直方向上速度和方向均有切变的风相互作用,上升气流在对流层的中部开始旋转,形成中尺度气旋。

(3)随着中尺度气旋向地面发展和向上伸展,它本身变细并增强。同时,一个小面积的增强辅合,即初生的龙卷在气旋内部形成,产生气旋的同样过程,形成龙卷核心。

(4)龙卷核心中的旋转与气旋中的不同,它的强度足以使龙卷一直伸展到地面。当发展的涡旋到达地面高度时,地面气压急剧下降,地面风速急剧上升,形成龙卷。
翻译一下

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 strengthened
In 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 necessitated
With 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 core
A 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
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第1个回答  2011-07-19
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