How to track a tornado - Karen Kosiba

譯者: Wei Chang 審譯者: Max Chern

So, I think all good tornado talks need to start

我想每個關龍捲風的優秀演講

都是用精彩的龍捲風相片作為開頭

with an awesome tornado shot.

And this is not that awesome tornado shot.

但這張並不是那種精彩的龍捲風相片

That was the first tornado I ever saw, it was really cool, really scary,

這是我第一次看見的龍捲風

很酷、很可怕

and I'm showing it to you guys

我把這張相片展示給你們看

因為這是我起初進入這領域的理由

because that's why I got into the field in the first place.

所以即使這張照片沒拍好

So even though it's a bad photograph,

it was really cool to be out there the first time.

能第一次親眼見到龍捲風還是很酷

不過現在我在拍的是真正的龍捲風影片

But now I'm taking real tornado footage.

Fast forward a few years.

向前快轉幾年

This is a few years ago, during a field project called VORTEX2,

幾年前，我參與一個

名為 VORTEX2 的實地勘查計畫

where myself and a bunch of other scientists were out there,

我和一群科學家一起

帶著各種儀器圍著龍捲風

surrounding tornadoes with different types of instrumentation

and trying to figure out how tornadoes form.

試著找出龍捲風的成因

It's a big question we're trying to answer.

那是我們試圖回答的大哉問

It sounds like a very basic one,

聽起來很基本

but it's something we're still trying to figure out.

但我們仍在努力找出答案

我們也想了解

We're also still trying to figure out what the winds are like near the surface.

靠近地表的地方，風是怎麼吹的

We know what the winds are like above building level,

我們知道建築高度以上的風如何運作

但我們真的不知道地表處的情形

but we really don't know what they're like at the surface

以及這兩者之間的關聯

and how that relates to what we're seeing above building level.

大部分的龍捲風成形於超大胞雷暴

Most tornadoes form from what we call supercell thunderstorms.

Supercell thunderstorms are what you commonly think of

超大胞雷暴一般會被想成

帶來龍捲風的風暴

as tornado-raising storms.

They're big, rotating thunderstorms

那是大型、會旋轉的雷暴

that happen a lot of times in the midsection of the United States.

常常發生在美國中部

But the problem is that even though they're rotating up above,

但問題是，即使它們上層正在旋轉

it doesn't mean they're rotating at the surface.

不代表靠近地表的地方也有在轉

當我們研究這些風暴

And when we look at these storms

這些照片、這些我們手中的資料

and at these pictures and at the data we have,

they all kind of look the same.

它們看起來好像都一樣

當我們試著發佈龍捲風預報或警告

And it's really problematic

if we're trying to make tornado forecasts or warnings,

就會產生許多問題

because we only want to warn or forecast about the storms

因為我們只想要預警或預測

that are going to actually make a tornado.

那些真的會形成龍捲風的風暴

One of the big, critical distinguishing features, we think, between these storms,

我們認為，這些風暴之間 最大、最關鍵的區別

和後側緣下沉氣流有關

is something about the rear-flank downdraft.

So these big rotating thunderstorms have this downdraft

這種下沉氣流

環繞在這些大型旋轉的雷暴雨的後側邊緣

that wraps around the rear edge of it,

hence the "rear-flank" downdraft.

因此被稱為「後側緣」下沉氣流

But we think how warm that is, how buoyant that air is,

我們也認為其溫度、空氣浮力

and then also how strong the updraft it's wrapping into,

以及上升氣流將空氣吸入的力度

makes a big difference on whether or not it's going to make a tornado.

都與龍捲風是否能形成息息相關

There's a lot more that goes into it --

還有更多需要考慮的事情

I'll tell you about that in a second.

我馬上就會告訴你們

一旦龍捲風確實再次成形

Once you actually get a tornado, again, the problem that we have

我們要思考的問題就變成

is getting measurements near the surface.

要如何測量靠近地表的數據

It's really hard to get measurements near the surface --

要能得到靠近地表的數據真的很難－－

人大多不會願意開車闖進龍捲風中

most people don't want to drive into tornadoes.

There are a few exceptions; you might have seen them on TV shows.

當然有些例外， 你可能在電視節目中看過

But most people don't want to do that.

但大部分的人都不會想這麼做的

Even getting instrumentation in the path of the tornado is pretty tricky, too.

要把儀器放到龍捲風 行經路徑上也不容易

Because, again, you don't want to be that close to a tornado

因為，同樣地，你不會想離龍捲風那麼近

有時候龍捲風附近的風也很強勁

because sometimes the winds around the tornado are strong as well.

所以能得到確切位置的資訊 對我們來說很重要

So getting information, that critical location,

is key for us because, again, we don't know

因為我們不知道

if the winds that we're seeing above ground level,

我們在地表高度以上、建築高度以上

way above building level,

actually map to the surface,

所看見的是否與地面相符

if they're stronger, weaker, or about the same

不知道地面的風是否比建築高度以上

as what we're seeing above buildings.

強、弱，還是一樣

The way we get at answering a lot of these questions --

我們尋求這麼多問題解答的方式－－

and I'm an observationalist; I love to get out in the field,

我是名觀察學者，我喜歡實地勘查

收集龍捲風有關的資料

and collect data on tornadoes --

－－我們彙整了許多觀察結果

we compile a lot of observations.

我和一個團隊合作， 他們會操作機動雷達

I work with this group who operates mobile radars,

and they're exactly what they say -- basically, a radar

而他們就像他們自己所描述的－－

基本上就是一台載著雷達的藍色卡車

on the back of a big blue truck,

and we drive up really close to tornadoes to map out the winds.

我們會開到離龍捲風很近的地方， 記錄風

We map out the precipitation.

記錄降雨

We map out all these different things that are going on

記錄發生的一切事物

in order to better understand the processes in these storms.

以能更清楚地理解這些風暴的過程

底下這張照片

And that bottom there, that's what a tornado looks like

當你很靠近龍捲風並用雷達觀測它時

when you're looking at it with a mobile radar, and really close.

它看起來就是這樣子

Also, what we do is a lot of modeling,

我們常做的事情還有建構模組

so we do a lot of computer models and simulations,

所以我們在電腦上 建構很多模組、進行模擬

because the atmosphere is governed by the laws of physics.

因為大氣層受到物理法則制約

所以我們可以依據物理法則建模

So we can model the laws of physics

and see where the tornado might go,

看看龍捲風可能會怎麼移動

where the storm might go,

風暴怎麼移動

how strong the winds are near the surface

接近地表的風會有多強

and not actually have to go out in the field.

而無需真正進入現場

But of course, we want to have both observations and modeling

但是，我們當然想要觀察和建模並進

to move forward with the science.

讓兩者一起推動科學前進

這和我稍早之前給你們看的影片一樣

So, I showed you that video earlier that went real quick, too.

移動得很快速

This is what it looks like, looking at it with a radar.

這是那個影片在雷達上呈現的樣貌

So you saw it visually,

所以你用雙眼看見它了

but this is what I get really excited about when I see now in the field,

但如今會讓我真的興奮起來的

是在現場看見像這樣的圖

stuff that looks like this.

看見這樣的圖會讓我們興奮的原因是

The really exciting thing about looking at stuff like this

我們在風暴尚未形成龍捲風前 捕獲到它了

is that we caught this storm from when it didn't make a tornado

to when it made a tornado and intensified

記錄到龍捲風形成、加劇

and when it dissipated.

以及它消散的時刻

This is the one of the rare data sets that we have out there

這是我們在實地勘查過程中 罕見能得的資料

that were able to study the entire life cycle of a tornado.

我們可以藉此研究龍捲風完整的生成週期

I talked about how we think that rear-flank downdraft is important

我提過我們認為後側緣下沉氣流很重要

because it tilts, there's a lot of spin in the atmosphere,

因為它是傾斜的

大氣層中有許多旋轉氣流

but the problem with all this spin in the atmosphere

但問題是所有這些旋轉的氣流

is it needs to be oriented vertically,

方向必須要是垂直的

because that's what tornadoes are doing,

因為那是龍捲風運作的方式

and it needs to orientated vertically near the ground.

在接近地表的地方，方向要是垂直的

所以我們認為 這種後側緣下沉氣流如同脈搏

So we think this rear-flank downdraft just pulses.

And these pulses in this rear-flank downdraft, we think,

這些後側緣下沉氣流中的脈搏

are very important for converging that rotation,

對聚集旋轉氣流而言非常重要

but also getting that rotation into the right place.

也能讓這些旋轉氣流進到該去的位置

我們認知到另一件事

Other things we've learned

is that we have gotten a bunch of fortuitous measurements

在龍捲風行經路徑上 和非常接近地面的地方

in the path of the tornadoes and very near the surface.

我們取得許多偶然的測量值

And we found out

我們發現，在地面附近的風

that the winds near the surface are actually pretty comparable

其實和我們在離地面三、四十公尺高

to what we're seeing 30, 40 meters above ground level.

所觀察到的差不多

So there's not a big reduction in what we're seeing above the surface

我們在地面所見到房屋高度所見

測量值並沒有大幅降低

to what we're seeing at house level.

And that was a pretty surprising finding for us,

這結果對我們來說滿令人訝異的

因為我們原先滿肯定地認為

because we kind of assumed that the winds decrease

風速會在近地面處大幅減少

pretty substantially near the surface.

我想很快地用這張圖結束這次演講

I'm going to end with this real quick.

And this is not my last tornado I ever saw,

這不是我見過的最後一個龍捲風

but I really like this image,

但我很喜歡這張圖

because this was taken with one of those mobile radars I was talking about.

因為這是用我提到的 其中一台機動雷達拍攝的

這是龍捲風，不是颶風

This is a tornado, not a hurricane,

當你真的很靠近它時，它長得像這樣

and this is what it looks like when you're really close to it.

我覺得這很神奇

And I find this amazing,

我們真的可以運用科技 如此接近這樣的風暴

that we can actually take technology this close to these types of storms

and see these inner workings.

並且觀察到內部的情形

And for those of you who look at tornado images often,

如果你們常看龍捲風的圖片

you can see there's a lot going on -- there's rain spiraling,

你們會看出這裡面顯示出很多事情

雨水在螺旋上升

and you can actually see the debris cloud associated with this tornado.

也能看見因這場龍捲風出現的碎片雲

我十分期待未來與未來科技

I look forward to the future and future technologies

and being able to learn a lot more about these storms,

也很期待可以更加了解這些風暴

as the world advances,

讓世界更進步

as you guys contribute to the science

因為你們對科學有所貢獻

and we're able to really learn more about how tornadoes form.

我們能更加了解龍捲風形成的原因

Thank you.

謝謝各位！

(Applause)

（掌聲）

翻譯：Wei Chang