未登录,请登录后再发表信息
最新评论 (0)
播放视频

洋流是如何运转的?

How do ocean currents work? - Jennifer Verduin

1992年 一艘装载着洗浴玩具的货船
In 1992, a cargo ship carrying bath toys got caught in a storm.
遭遇了风暴 货物被冲入海中
Shipping containers washed overboard,
海浪将28000只橡胶鸭和其它玩具冲卷入北太平洋
and the waves swept 28,000 rubber ducks and other toys into the North Pacific.
但是它们没有集中在一起
But they didn’t stick together.
恰恰相反——
Quite the opposite– the ducks have
橡皮鸭被冲至世界各地
since washed up all over the world,
而研究者则利用它们的漂流轨迹
and researchers have used their paths
绘制洋流图 以更好地了解它
to chart a better understandingof ocean currents.
洋流受到多个因素的驱使:
Ocean currents are drivenby a range of sources:
风、潮汐、海水的密度变化
the wind, tides, changes in water density,
和地球的自转
and the rotation of the Earth.
洋底的地形和海岸线的形态
The topography of the ocean floor
影响着洋流的动态
and the shoreline modifies those motions,
使它们或增速 或减速 或改变方向
causing currents to speed up, slow down, or change direction.
洋流分为两种:
Ocean currents fall intotwo main categories:
表层流和深海洋流
surface currents and deep ocean currents.
表层流控制着顶层10%的海水的动向
Surface currents control the motion of the top 10 percent

of the ocean’s water,
深海洋流驱动着其它90%的海水
while deep-ocean currents mobilizethe other 90 percent.
虽然这两种洋流的成因不同
Though they have different causes,
但这两种洋流相互影响
surface and deep ocean currents influence each other
以一种复杂的舞蹈保持海水的涌动近岸
in an intricate dance that keepsthe entire ocean moving.

Near the shore,
风和潮汐推动着表层流
surface currents are driven by both the wind and tides,
使得海水随着海水位的升降
which draw water back and forth as the water level falls and rises. Meanwhile,
前进或后退 同时 在开阔的洋面上
in the open ocean,
风是驱动表层流的主要力量
wind is the major force behind surface currents.
当风吹过洋面时
As wind blows over the ocean,
顶层的海水随它流动
it drags the top layers of water along with it.
流动的顶层海水带动了下层的海水
That moving water pulls onthe layers underneath,
下层的海水又带动了更下一层的海水事实上
and those pull on the ones beneath them.
深至400米的海水
In fact, water as deep as 400 meters
仍受海水表面的风的影响
is still affected by the windat the ocean’s surface.
如果你身处高空
If you zoom out to look at the patterns
观察世界各处洋流的流动模式
of surface currents all over the earth,
就会发现它们形成了被称为“流涡”的巨大回路
you’ll see that they formbig loops called gyres,
在北半球顺时针流动
which travel clockwisein the northern hemisphere
而在南半球逆时针流动
and counter-clockwisein the southern hemisphere.
这是因为地球自转的方式
That’s because of the waythe Earth’s rotation
影响着造就洋流的大气环流
affects the wind patterns thatgive rise to these currents.
如果地球不自转
If the earth didn’t rotate,
大气和海水就只会
air and water would simply move back and forth
在赤道的低压带和两极的高压带之间
between low pressure at the equator
来回移动
and high pressure at the poles.
但实际上地球在自转
But as the earth spins,
从赤道吹向北极
air moving from the equator to
的风向东偏转
the North Pole is deflected eastward,
而自北极向南吹的风向西偏转
and air moving back downis deflected westward.
南半球的情况则像是个镜像翻转
The mirror image happensin the southern hemisphere,
所以风的主流 在海盆上形成了回路状的图案
so that the major streams of wind form loop-like patterns around the ocean basins.
这就是所谓的“科里奥利效应”
This is called the Coriolis Effect.
流动的大气推动其下的海水形成了同样的流涡
The winds push the ocean beneath them into the same rotating gyres.
因为水比大气更容易吸收热量
And because water holds onto heatmore effectively than air,
所以洋流促进了热量在全球范围内的流动
these currents help redistributewarmth around the globe.
与表层流不同
Unlike surface currents,
深海洋流的产生主要缘于海水密度的变化
deep ocean currents are driven primarily by changes in the density of seawater.
当海水向北极流动时
As water moves towards the North Pole,
水温逐渐降低
it gets colder.
同时海水也有了更高的含盐量
It also has a higherconcentration of salt,
因为冰晶使水凝固 而盐仍留在水中
because the ice crystals that form trap water while leaving salt behind.
这种冷且含盐度高的海水的密度越来越高
This cold, salty water is more dense,
所以它向下沉 而温暖的表层流取代了它的位置
so it sinks, and warmer surface water takes its place,
这便形成了被称作“热盐环流”的垂直洋流
setting up a vertical current calledthermohaline circulation.
由深层海水和受风驱使的表层流构成的热盐循环
Thermohaline circulation of deep waterand wind-driven surface currents
构成了曲曲折折的回路——全球传送带
combine to form a winding loopcalled the Global Conveyor Belt.
海水从洋底升至表层
As water moves from the depths

of the ocean to the surface,
携带着滋养微生物的营养物质
it carries nutrients that nourish themicroorganisms
而这些微生物正是许多海洋食物链的基础
which form the base of manyocean food chains.
全球传送带是世界上最长的洋流
The global conveyor belt is thelongest current in the world,
蜿蜒环绕着整个地球
snaking all around the globe.
但它每分钟只移动几厘米
But it only moves a fewcentimeters per second.
对于一滴海水来说
It could take a drop
做一次完整的旅行需要花上一千年
of water a thousand years to make the full trip. However,
然而 上升的海平面似乎
rising sea temperatures arecausing the conveyor belt
使得传送带的速度慢了下来
to seemingly slow down.
相关模型显示 这正对大西洋两岸的天气
Models show this causing havoc withweather systems
系统造成严重破坏
on both sides of the Atlantic,
而且人们无从得知
and no one knows what would happen
如果传导持续减慢
if it continues to slow
或干脆停下来的话 会有怎样的后果
or if it stopped altogether.
正确预测并
The only way we’ll
做好相应防备的唯一方法
be able to forecast correctly and prepare accordingly
是持续研究洋流和造就它们的巨大力量
will be to continue to study currents and the powerful forces that shape them.

发表评论

译制信息
视频概述
听录译者

收集自网络

翻译译者

收集自网络

审核员

自动通过审核

视频来源

https://www.youtube.com/watch?v=p4pWafuvdrY

相关推荐