To form a tornado, cold air must sit above warm and moist air, and the wind needs to go in different directions at different heights, creating shear forces.

形成龙卷风，寒冷的空气必须处在暖湿的空气上部，而风应该在不同高度向不同的方向运动，以此创造出剪切力。

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Inside the tornado probe, there are sensors to measure wind speed, temperature, pressure, and direction.

龙卷风探测仪的内部安装有传感器以测量风速、温度、压力和风向。

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Researchers say that rapidly changing contrasts in wind and temperatures in an area just a few miles across can spawn a tornado in a matter of minutes.

研究员说，在仅有覆盖几英里的区域内，急剧变化的风和温度就可以在几分钟之内生成龙卷风。

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It takes the right combination of wind,temperature,pressure and humidity to create even a weak tornado.

VOA: special.2010.05.11

Tornado seasons are the result of wind and weather patterns.

VOA: special.2010.05.11

The NRC determined that the design-basis tornado wind speeds for new reactors should correspond to the exceedance frequency of one-in-ten-million per year.

FORBES: Tornados and Nukes -- How Big Can They Get?

The Fujita scale is used to estimate the wind speed of a tornado by the damage the tornado causes.

CNN: Tornadoes Fast Facts

"Through embedded sensors, the probes can measure a tornado's wind speed and direction, barometric pressure, humidity, and temperature, " the magazine wrote.

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