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  • They call me the tornado chaser.


  • When the wind is up and conditions are right, I get in my car and follow violent storms.


  • "Crazy," you say? Perhaps, but really I chase these sky beasts to learn about them.


  • I want to share with you what I know.


  • Tornadoes are rapidly rotating columns of air that form inside storms then connect with the ground via a funnel of cloud.


  • When that happens, they tear across the Earth, posing a huge threat to life and property.


  • Because of this, there's a great deal of research into these phenomena, but the truth is, there's still a lot we don't know about how tornadoes form.

    為此有很多針對這個天然災害的研究,但對它形成的原因, 仍有許多未解之謎。

  • The conditions that may give rise to one tornado won't necessarily cause another.


  • But we have learned a lot since people first started recording tornadoes, like how to recognize the signs when one is brewing in the sky.


  • Are you coming along for the ride?


  • Tornadoes begin with a thunderstorm but not just any thunderstorm.

    龍捲風的前兆是雷雨, 但不是普通的雷雨。

  • These are especially powerful, towering thunderstorms called supercells.


  • Reaching up to over 50,000 feet, they bring high force winds, giant hailstones, sometimes flooding and great flashes of lightning, too.


  • These are the kinds of storms that breed tornadoes, but only if there are also very specific conditions in place, clues that we can measure and look out for when we're trying to forecast a storm.

    這些是孕育龍捲風的風暴,但還要再滿足一些特定條件,那些我們可以測量、察覺到, 幫助我們預測龍捲風的指標。

  • Rising air is the first ingredient needed for a tornado to develop.


  • Any storm is formed when condensation occurs, the byproducts of the clouds.


  • Condensation releases heat, and heat becomes the energy that drives huge upward drafts of air.


  • The more condensation and the bigger the storm clouds grow, the more powerful those updrafts become.


  • In supercells, this rising air mass is particularly strong.

    在超級雷雨胞中, 這種上升的氣團特別強大。

  • As the air climbs, it can change direction and start to move more quickly.


  • Finally, at the storm's base, if there is a lot of moisture, a huge cloud base develops, giving the tornado something to feed off later, if it gets that far.

    最後,如果水氣夠的話,在風暴的基底,會發展成巨大的「雲底」,如果龍捲風形成, 就能在之後為其提供所需的能量。

  • When all these things are in place, a vortex can develop enclosed by the storm, and forming a wide, tall tube of spinning air that then gets pulled upwards.

    當一切就緒, 雲團中心會形成渦流,再發展成向上吸引的巨大管狀旋風。

  • We call this a mesocyclone.


  • Outside, cool, dry, sinking air starts to wrap around the back of this mesocyclone, forming what's known as a rear flank downdraft.


  • This unusual scenario creates a stark temperature difference between the air inside the mesocyclone, and the air outside, building up a level of instability that allows a tornado to thrive.

    這樣特殊的現象會造成中氣旋裡外強烈的溫差,從而形成一定程度的不穩定性, 進一步助長龍捲風壯大。

  • Then, the mesocyclone's lower part becomes tighter, increasing the speed of the wind.


  • If, and that's a big if, this funnel of air moves down into that large, moist cloud base at the bottom of the parent storm,

    如果,我是說假如, 這個漏斗狀的氣旋往下移,接觸到雷雨胞下層潮濕豐沛的雲底,

  • it sucks it in and turns it into a rotating wall of cloud, forming a link between the storm that created it and the Earth.

    就會吸收雲底變成快速旋轉的雲牆, 最後再向下觸及地面。

  • The second that tube of spinning cloud touches the ground, it becomes a tornado.


  • Most are small and short-lived, producing winds of 65-110 miles per hour, but others can last for over an hour, producing 200 mile per hour winds.

    龍捲風大多小又短命, 風速約每小時 65 到 110 英里,但有些風速可達每小時 200 英里, 而且維持一個小時左右。

  • They are beautiful but terrifying, especially if you or your town is in its path.


  • In that case, no one, not even tornado chasers like me, enjoy watching thing unfold.


  • Just like everything, however, tornadoes do come to an end.

    就跟萬物一樣, 龍捲風也有走到盡頭的時候。

  • When the temperature difference disappears and conditions grow more stable, or the moisture in the air dries up, the once fierce parent storm loses momentum and draws its tornado back inside.


  • Even so, meteorologists and storm chasers like me will remain on the lookout, watching, always watching to see if the storm releases its long rope again.

    儘管到了這個階段, 氣象學家或追風少年如我仍在密切關注,一直在觀察暴風雨什麼時候再次放下它的長繩。

They call me the tornado chaser.


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B2 中高級 中文 美國腔 TED-Ed 龍捲風 形成 氣流 地面 風暴

【TED-Ed】龍捲風是如何形成的? How do tornadoes form? - James Spann (How do tornadoes form? - James Spann)

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    Ashley Chen 發佈於 2020 年 10 月 20 日