How to track a tornado - Karen Kosiba
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0:06 - 0:09So, I think all good
tornado talks need to start -
0:09 - 0:11with an awesome tornado shot.
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0:11 - 0:13And this is not that awesome tornado shot.
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0:13 - 0:17That was the first tornado I ever saw,
it was really cool, really scary, -
0:17 - 0:18and I'm showing it to you guys
-
0:18 - 0:21because that's why I got
into the field in the first place. -
0:21 - 0:23So even though it's a bad photograph,
-
0:23 - 0:25it was really cool
to be out there the first time. -
0:25 - 0:27But now I'm taking real tornado footage.
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0:27 - 0:29Fast forward a few years.
-
0:29 - 0:32This is a few years ago,
during a field project called VORTEX2, -
0:32 - 0:35where myself and a bunch
of other scientists were out there, -
0:35 - 0:38surrounding tornadoes
with different types of instrumentation -
0:38 - 0:40and trying to figure out
how tornadoes form. -
0:40 - 0:42It's a big question
we're trying to answer. -
0:42 - 0:44It sounds like a very basic one,
-
0:44 - 0:46but it's something
we're still trying to figure out. -
0:46 - 0:50We're also still trying to figure out
what the winds are like near the surface. -
0:50 - 0:52We know what the winds are like
above building level, -
0:52 - 0:55but we really don't know
what they're like at the surface -
0:55 - 0:58and how that relates
to what we're seeing above building level. -
0:58 - 1:01Most tornadoes form from what we call
supercell thunderstorms. -
1:01 - 1:04Supercell thunderstorms
are what you commonly think of -
1:04 - 1:06as tornado-raising storms.
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1:06 - 1:07They're big, rotating thunderstorms
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1:07 - 1:11that happen a lot of times
in the midsection of the United States. -
1:11 - 1:14But the problem is that even though
they're rotating up above, -
1:14 - 1:17it doesn't mean they're rotating
at the surface. -
1:17 - 1:18And when we look at these storms
-
1:18 - 1:20and at these pictures
and at the data we have, -
1:20 - 1:22they all kind of look the same.
-
1:22 - 1:23And it's really problematic
-
1:23 - 1:26if we're trying to make
tornado forecasts or warnings, -
1:26 - 1:29because we only want to warn
or forecast about the storms -
1:29 - 1:31that are going to actually make a tornado.
-
1:31 - 1:35One of the big, critical distinguishing
features, we think, between these storms, -
1:35 - 1:38is something about
the rear-flank downdraft. -
1:38 - 1:41So these big rotating thunderstorms
have this downdraft -
1:41 - 1:43that wraps around the rear edge of it,
-
1:43 - 1:44hence the "rear-flank" downdraft.
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1:44 - 1:48But we think how warm that is,
how buoyant that air is, -
1:48 - 1:51and then also how strong
the updraft it's wrapping into, -
1:51 - 1:54makes a big difference on whether or not
it's going to make a tornado. -
1:54 - 1:56There's a lot more that goes into it --
-
1:56 - 1:58I'll tell you about that in a second.
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1:58 - 2:01Once you actually get a tornado,
again, the problem that we have -
2:01 - 2:04is getting measurements near the surface.
-
2:04 - 2:06It's really hard to get measurements
near the surface -- -
2:06 - 2:09most people don't want
to drive into tornadoes. -
2:09 - 2:12There are a few exceptions;
you might have seen them on TV shows. -
2:12 - 2:13But most people don't want to do that.
-
2:13 - 2:17Even getting instrumentation in the path
of the tornado is pretty tricky, too. -
2:17 - 2:20Because, again, you don't want
to be that close to a tornado -
2:20 - 2:23because sometimes the winds
around the tornado are strong as well. -
2:23 - 2:26So getting information,
that critical location, -
2:26 - 2:28is key for us because,
again, we don't know -
2:28 - 2:30if the winds that we're seeing
above ground level, -
2:30 - 2:32way above building level,
-
2:32 - 2:33actually map to the surface,
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2:33 - 2:36if they're stronger, weaker,
or about the same -
2:36 - 2:38as what we're seeing above buildings.
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2:38 - 2:40The way we get at answering
a lot of these questions -- -
2:40 - 2:43and I'm an observationalist;
I love to get out in the field, -
2:43 - 2:45and collect data on tornadoes --
-
2:45 - 2:46we compile a lot of observations.
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2:46 - 2:49I work with this group
who operates mobile radars, -
2:49 - 2:51and they're exactly
what they say -- basically, a radar -
2:51 - 2:53on the back of a big blue truck,
-
2:53 - 2:56and we drive up really close
to tornadoes to map out the winds. -
2:56 - 2:57We map out the precipitation.
-
2:57 - 3:00We map out all these
different things that are going on -
3:00 - 3:03in order to better understand
the processes in these storms. -
3:03 - 3:06And that bottom there,
that's what a tornado looks like -
3:06 - 3:10when you're looking at it
with a mobile radar, and really close. -
3:10 - 3:12Also, what we do is a lot of modeling,
-
3:12 - 3:14so we do a lot of computer
models and simulations, -
3:14 - 3:17because the atmosphere
is governed by the laws of physics. -
3:17 - 3:19So we can model the laws of physics
-
3:19 - 3:21and see where the tornado might go,
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3:21 - 3:22where the storm might go,
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3:22 - 3:24how strong the winds are near the surface
-
3:24 - 3:26and not actually have
to go out in the field. -
3:27 - 3:29But of course, we want to have
both observations and modeling -
3:29 - 3:31to move forward with the science.
-
3:31 - 3:35So, I showed you that video earlier
that went real quick, too. -
3:35 - 3:38This is what it looks like,
looking at it with a radar. -
3:38 - 3:39So you saw it visually,
-
3:39 - 3:42but this is what I get really excited
about when I see now in the field, -
3:42 - 3:44stuff that looks like this.
-
3:44 - 3:46The really exciting thing
about looking at stuff like this -
3:46 - 3:49is that we caught this storm
from when it didn't make a tornado -
3:49 - 3:51to when it made a tornado and intensified
-
3:51 - 3:52and when it dissipated.
-
3:52 - 3:55This is the one of the rare data sets
that we have out there -
3:55 - 3:59that were able to study
the entire life cycle of a tornado. -
3:59 - 4:02I talked about how we think
that rear-flank downdraft is important -
4:02 - 4:05because it tilts, there's a lot
of spin in the atmosphere, -
4:05 - 4:08but the problem with
all this spin in the atmosphere -
4:08 - 4:10is it needs to be oriented vertically,
-
4:10 - 4:12because that's what tornadoes are doing,
-
4:12 - 4:14and it needs to orientated
vertically near the ground. -
4:14 - 4:17So we think this rear-flank
downdraft just pulses. -
4:17 - 4:20And these pulses in this
rear-flank downdraft, we think, -
4:20 - 4:22are very important
for converging that rotation, -
4:22 - 4:25but also getting that rotation
into the right place. -
4:25 - 4:27Other things we've learned
-
4:27 - 4:29is that we have gotten
a bunch of fortuitous measurements -
4:29 - 4:32in the path of the tornadoes
and very near the surface. -
4:32 - 4:33And we found out
-
4:33 - 4:36that the winds near the surface
are actually pretty comparable -
4:36 - 4:39to what we're seeing 30, 40 meters
above ground level. -
4:39 - 4:42So there's not a big reduction
in what we're seeing above the surface -
4:42 - 4:44to what we're seeing at house level.
-
4:44 - 4:46And that was a pretty
surprising finding for us, -
4:46 - 4:49because we kind of assumed
that the winds decrease -
4:49 - 4:51pretty substantially near the surface.
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4:51 - 4:53I'm going to end with this real quick.
-
4:53 - 4:55And this is not my last
tornado I ever saw, -
4:55 - 4:57but I really like this image,
-
4:57 - 5:00because this was taken with one of those
mobile radars I was talking about. -
5:00 - 5:02This is a tornado, not a hurricane,
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5:02 - 5:05and this is what it looks like
when you're really close to it. -
5:05 - 5:06And I find this amazing,
-
5:06 - 5:10that we can actually take technology
this close to these types of storms -
5:10 - 5:11and see these inner workings.
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5:11 - 5:14And for those of you who look
at tornado images often, -
5:14 - 5:17you can see there's a lot going on --
there's rain spiraling, -
5:17 - 5:20and you can actually see the debris cloud
associated with this tornado. -
5:20 - 5:23I look forward to the future
and future technologies -
5:23 - 5:26and being able to learn
a lot more about these storms, -
5:26 - 5:27as the world advances,
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5:27 - 5:29as you guys contribute to the science
-
5:29 - 5:32and we're able to really learn
more about how tornadoes form. -
5:32 - 5:33Thank you.
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5:33 - 5:35(Applause)
- Title:
- How to track a tornado - Karen Kosiba
- Description:
-
View full lesson: http://ed.ted.com/lessons/how-to-track-a-tornado-karen-kosiba
Atmospheric scientist Karen Kosiba studies how tornadoes form and do damage. Getting measurements near the surface of these twisters is difficult, though, and driving into them is a practice mostly reserved for the big screen. In this TEDYouth Talk, Kosiba describes how she and her team use observations and modeling to track these super storms, while sharing some incredible footage from the field.
Talk by Karen Kosiba.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:45
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Krystian Aparta
The English transcript was updated on 2/19/2016.