Activa JavaScript para disfrutar de los vídeos de la Mediateca.
Surface Current
Ajuste de pantallaEl ajuste de pantalla se aprecia al ver el vídeo en pantalla completa. Elige la presentación que más te guste:
Fourth segment of the Ocean Odyssey describes surface currents, what role they have in the creation of climate and how they form.
Hi, Bianca. Thanks for meeting me here. I had a taping earlier today.
00:00:00
That's cool. I've had a little bit of experience in front of cameras.
00:00:07
Dr. Adamant, we learned about density currents,
00:00:11
but we need to learn more about surface currents.
00:00:14
So what exactly is a surface current?
00:00:17
A surface current is water moving near the ocean's surface,
00:00:19
above what we call the thermocline.
00:00:22
Thermocline. I know that therm has something to do with temperature.
00:00:24
Right. And cline means change.
00:00:28
So the thermocline is a region of temperature change.
00:00:31
Where is the thermocline?
00:00:34
Typically between 50 and 150 meters deep.
00:00:36
So how do surface currents form?
00:00:39
Friction between the wind and the surface water causes that water to move.
00:00:41
We learned in the case of the mysterious red light about global wind patterns,
00:00:46
and that winds blow in a certain direction depending upon where they're located on Earth.
00:00:50
Right. For example, the trade winds push the surface currents around in the tropics.
00:00:54
But are there other factors?
00:01:00
Sure. Because the Earth rotates, there's turning due to the Coriolis effect.
00:01:02
Isn't that when the wind is deflected to the right in the northern hemisphere
00:01:06
and the left in the southern hemisphere?
00:01:10
Yes. And another factor that steers currents is the topography,
00:01:12
the hills and valleys on the ocean floor.
00:01:16
How does the topography underwater affect the surface currents?
00:01:19
I'll show you.
00:01:23
Sit on the stool.
00:01:28
Now don't try this without an adult, but I want you to stick your arms and legs out.
00:01:31
And once I spin you, I want you to bring your arms and legs in close to your body.
00:01:36
Okay? You ready?
00:01:40
What happened?
00:01:50
I spun slower when my arms and legs were out and faster when they were in.
00:01:51
Topography does the same thing to currents.
00:01:58
If a current flows over an underwater mountain,
00:02:00
the water column gets flattened and compresses.
00:02:03
That's you with your legs out.
00:02:06
The water spins differently, and the currents get deflected.
00:02:08
Why are some surface currents cold and some others warm?
00:02:12
It depends on where the water's coming from.
00:02:15
If it's coming from the poles, it's cold.
00:02:18
If it's from the tropics, it's warm.
00:02:21
Do warm and cold currents affect the climate of an area?
00:02:23
That's a good question, Bianca. Yes, they do.
00:02:26
For example, Ireland is pretty far north, and you might expect it to be cold there.
00:02:29
But the Gulf Stream flows past Ireland,
00:02:33
and the warm water heats the air, which helps to create a surprisingly mild climate.
00:02:36
They even have palm trees in Ireland.
00:02:40
Really?
00:02:43
With currents located in every ocean,
00:02:45
I guess they could be responsible for bringing the tennis shoes and oil to our beach.
00:02:47
It's possible, but you've got to be careful.
00:02:51
The same current can transport things to different places.
00:02:54
How does that happen?
00:02:57
You drop the balls at the same time and all in about the same place.
00:03:09
They ended up in different places. Why?
00:03:13
Is it because there are so many different variables,
00:03:16
such as the pits in the pavement or even the shape of the ball?
00:03:19
Exactly. The same thing happens in the ocean.
00:03:22
Tiny variations in the current can lead to large differences
00:03:26
where the current might actually move things like your tennis shoes.
00:03:30
Wow, that's amazing. I'm curious.
00:03:33
Why does NASA study currents?
00:03:37
First, oceans have the greatest influence on climate.
00:03:39
And only from space can we monitor the vast oceans on a global scale
00:03:42
and monitor critical changes in the currents and the heat storage.
00:03:46
Why is that so important?
00:03:50
Well, the oceans cover 70 percent of the Earth,
00:03:52
and the currents in the ocean are an important part of the water cycle.
00:03:55
Any change in the water cycle can cause major consequences on our Earth.
00:03:59
How does NASA monitor the ocean?
00:04:03
We use different satellites to monitor things like currents, waves, temperature,
00:04:05
and pretty soon even salinity.
00:04:11
That's really interesting.
00:04:13
I'm always amazed at all the research NASA does to help protect our Earth.
00:04:15
Thanks, Dr. Adamek. This information has been very helpful.
00:04:19
You're welcome. And call if you have any more questions.
00:04:22
- Valoración:
- Eres el primero. Inicia sesión para valorar el vídeo.
- 1
- 2
- 3
- 4
- 5
- Idioma/s:
- Niveles educativos:
- ▼ Mostrar / ocultar niveles
- Nivel Intermedio
- Autor/es:
- NASA LaRC Office of Education
- Subido por:
- EducaMadrid
- Licencia:
- Reconocimiento - No comercial - Sin obra derivada
- Visualizaciones:
- 727
- Fecha:
- 28 de mayo de 2007 - 15:34
- Visibilidad:
- Público
- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 04′ 27″
- Relación de aspecto:
- 4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
- Resolución:
- 480x360 píxeles
- Tamaño:
- 26.86 MBytes