ABOUT THE SPEAKER
Kristin Poinar - Glaciologist
Kristin Poinar uses remote sensing and numerical models to study the interaction of meltwater with ice flow, especially on the Greenland Ice Sheet.

Why you should listen

Hidden under many meters of ice, a pool of meltwater lies under the Greenland Ice Sheet. Kristin Poinar studies how the meltwater forms and flows in this dynamic glacial system. She asks: How did this water get there, and where does it go? How much water is in there? And how is climate change affecting this system?

Using data from Operation IceBridge flights and from field instruments, she's building a numerical model of how crevasses form and channel water. In fact, a NASA report released in February 2017 revealed a new pathway her team discovered for meltwater to reach the ocean. Using physically based models to constrain the bounds of what is realistic has shaped Poinar's interest in glaciology.

Poinar is currently a postdoctoral researcher at NASA Goddard Space Flight Center. She will be moving to the University at Buffalo in winter 2017 to be a professor in the Geology Department and the RENEW Institute.

More profile about the speaker
Kristin Poinar | Speaker | TED.com
TED2017

Kristin Poinar: What's hidden under the Greenland ice sheet?

克里斯汀·波伊娜: 格陵兰冰原之下的秘密

Filmed:
4,494,857 views

格陵兰冰原是巨大而神秘的,而它正在慢慢融化。依赖先进的科技,科学家们首次揭露了其中的奥秘,他们的发现令人叹为观止:冰原之下是一个巨大的含水层,包含了和太浩湖差不多水量的夏季融水。这些水是静止不动,还是会流入海洋导致海平面上升呢?加入冰川学家克里斯汀·波伊娜,共同发掘这片冰冻、被遗忘土地的探索之旅,来寻找答案吧。
- Glaciologist
Kristin Poinar uses remote sensing and numerical models to study the interaction of meltwater with ice flow, especially on the Greenland Ice Sheet. Full bio

Double-click the English transcript below to play the video.

00:12
When was I was 21 years年份 old,
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我21岁的时候
有很多物理作业
00:15
I had all this physics物理 homework家庭作业.
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00:17
Physics物理 homework家庭作业 requires要求 taking服用 breaks休息,
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做物理作业的时候需要休息
当时维基百科刚刚兴起
所以我经常在那儿浏览 放松
00:20
and Wikipedia维基百科 was relatively相对 new,
so I took a lot of breaks休息 there.
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00:24
I kept不停 going back to the same相同 articles用品,
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我总是看同一篇文章
反反复复地看
00:26
reading them again and again,
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关于冰川 南极洲和格陵兰岛的
00:28
on glaciers冰川, Antarctica南极洲 and Greenland格陵兰.
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00:33
How cool would it be to visit访问 these places地方
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如果能去那些地方该有多酷啊
需要做什么准备呢
00:35
and what would it take to do so?
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00:38
Well, here we are
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让我们来看看
在一辆被改造的空军客机上
00:39
on a repurposed改变用途 Air空气 Force cargo货物 plane平面
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客机由NASA操作
00:41
operated操作 by NASANASA
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从格陵兰岛的冰原上方飞过
00:43
flying飞行 over the Greenland格陵兰 ice sheet.
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00:46
There's a lot to see here,
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你可以看到很多东西
00:48
but there's more that is hidden,
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但是更多的是看不到的
00:49
waiting等候 to be uncovered裸露.
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等待被发掘
00:52
What the Wikipedia维基百科 articles用品 didn't tell me
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维基百科没有告诉我的是
在冰原下面有隐藏的液态水
00:54
is that there's liquid液体 water
hidden inside the ice sheet,
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00:58
because we didn't know that yet然而.
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因为当时没有人知道
01:02
I did learn学习 on Wikipedia维基百科
that the Greenland格陵兰 ice sheet is huge巨大,
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维基百科只告诉我
格陵兰岛的冰原面积极大
和墨西哥的大小差不多
01:05
the size尺寸 of Mexico墨西哥,
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01:06
and its ice from top最佳 to bottom底部
is two miles英里 thick.
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它的整个冰层足有2英里厚
01:10
But it's not just static静态的.
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但它并非静止不动
01:12
The ice flows流动 like a river
downhill下坡 towards the ocean海洋.
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冰块就像河水一样沿着山体流向海中
01:17
As it flows流动 around bends弯曲,
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当它流经弯道的时候
01:19
it deforms变形 and cracks裂缝.
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冰块会变形然后破裂
01:21
I get to study研究 these amazing惊人 ice dynamics动力学,
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我开始接触到这种惊人的冰学动态,
01:24
which哪一个 are located位于 in one of the most
remote远程 physical物理 environments环境
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它位于地球上现存的最荒僻的
自然环境中
01:27
remaining其余 on earth地球.
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01:29
To work in glaciology冰川 right now
is like getting得到 in on the ground地面 floor地板
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要立刻投入冰川学的工作
就像在20世纪末抢先创建 脸书 一样
01:33
at FacebookFacebook的 in the 2000s.
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01:35
(Laughter笑声)
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(笑)
01:37
Our capability能力 to fly airplanes飞机
and satellites卫星 over the ice sheets床单
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我们在冰原上方驾驶飞机
以及已有卫星的能力
正引发着冰川学的变革
01:40
is revolutionizing革新 glaciology冰川.
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01:42
It's just starting开始 to do for science科学
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它对于科学的作用
01:44
what the smartphone手机
has doneDONE for social社会 media媒体.
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就像智能手机对于社交媒体一样重要
01:47
The satellites卫星 are reporting报告
a wealth财富 of observations意见
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卫星报告的大量观测
01:50
that are revealing揭示 new hidden facts事实
about the ice sheets床单 continuously一直.
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都持续地发掘着冰原下的秘密
01:55
For instance, we have observations意见
of the size尺寸 of the Greenland格陵兰 ice sheet
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例如 我们有格陵兰岛冰原
大小的观测数据
01:59
every一切 month going back to 2002.
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从2002年至今的每个月都有
02:02
You can look towards the bottom底部
of the screen屏幕 here
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你们可以看到屏幕的下方
观察随着年月的增加带来的数据变化
02:04
to see the month and the year go forward前锋.
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你们可以看到在某些区域冰原融化
02:06
You can see that some areas
of the ice sheet melt熔化
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或是在夏天的时候彻底消融
02:09
or lose失去 ice in the summer夏季.
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02:11
Other areas experience经验 snowfall降雪
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其他的区域经历着降雪
02:13
or gain获得 ice back in the winter冬季.
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或是在冬天的时候重新结冰
02:16
This seasonal时令的 cycle周期, though虽然, is eclipsed黯然失色
by an overall总体 rate of mass loss失利
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然而这种季节周期性的变化
与总体质量的流失相比不值一提
这会使50年前的冰川学家目瞪口呆
02:21
that would have stunned目瞪口呆
a glaciologist冰川学家 50 years年份 ago.
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02:25
We never thought that an ice sheet could
lose失去 mass into the ocean海洋 this quickly很快.
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我们从未想过
冰原流失的速度会如此之快
02:31
Since以来 these measurements测量 began开始 in 2002,
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因为这些测量从2002年开始
02:33
the ice sheet has lost丢失 so much ice
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冰原已经有大量的冰流失
02:36
that if that water were piled up
on our smallest最少 continent大陆,
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如果那些融化的水积聚在澳大利亚这
这块世界上最小的大陆上
将会有膝盖那么深
02:39
it would drown Australia澳大利亚 knee-deep没膝深.
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02:42
How is this possible可能?
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这怎么可能呢
02:45
Well, under the ice lies the bedrock基岩.
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事实上 在冰的下面是基岩
02:48
We used radar雷达 to image图片 the hills丘陵,
valleys山谷, mountains and depressions洼地
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我们用雷达描绘山丘 峡谷
山脉和洼地的图像
02:53
that the ice flows流动 over.
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那些冰块川流过的地方
02:54
Hidden under the ice sheet are channels渠道
the size尺寸 of the Grand盛大 Canyon峡谷
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在冰原下是和美国大峡谷
一般大的海峡
成漏斗形 将格陵兰岛上的
冰和水导入海洋中
02:58
that funnel漏斗 ice and water
off of Greenland格陵兰 and into the ocean海洋.
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03:04
The reason原因 that radar雷达
can reveal揭示 the bedrock基岩
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雷达可以展现基岩的原因
在于对于雷达而言 冰是完全透明的
03:06
is that ice is entirely完全
transparent透明 to radar雷达.
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03:09
You can do an experiment实验.
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你们可以做一个实验
03:11
Go home and put
an ice cube立方体 in the microwave微波.
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回家把冰块放在微波炉中
03:14
It won't惯于 melt熔化,
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它不会融化
03:16
because microwaves微波炉, or radar雷达,
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因为微波或者雷达
03:18
pass通过 straight直行 through通过 the ice
without interacting互动.
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直接穿过冰块而不会对其发生作用
03:22
If you want to melt熔化 your ice cube立方体,
you have to get it wet湿,
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如果你想使冰块融化
应该先把它变湿
因为水在微波中容易升温
03:25
because water heats预赛 up easily容易
in the microwave微波.
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03:29
That's the whole整个 principle原理
the microwave微波 oven烤箱 is designed设计 around.
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那是微波炉的设计原理
03:32
Radar雷达 can see water.
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雷达看得见水
03:35
And radar雷达 has revealed透露
a vast广大 pool of liquid液体 water
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雷达显示了极大量的液态水
03:38
hidden under my colleague同事 Olivia奥利维亚,
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隐藏在我同事Olivia的脚下
03:40
seven stories故事 beneath下面 her feet.
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大概有七层楼高
03:43
Here, she's used a pump
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她正在用一个泵
将部分这些水运回冰原的表面
03:44
to bring带来 some of that water
back to the ice sheet's板材的 surface表面.
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03:47
Just six years年份 ago, we had no idea理念
this glacier冰川 aquifer含水层 existed存在.
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六年前 我们并不知道
这个冰川下方含水层的存在
03:53
The aquifer含水层 formed形成
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含水层形成于
03:55
when snow melts熔体 in the summer夏季 sun太阳
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雪在夏日下融化
03:57
and trickles涓涓细流 downward向下.
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然后慢慢地向下流
03:59
It puddles水坑 up in huge巨大 pools.
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它在巨大的水坑中搅动
04:02
From there, the snow acts行为 as an igloo雪屋,
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从那儿开始 雪就像冰屋一样
04:05
insulating绝缘 this water
from the cold and the wind above以上.
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将水与上方的寒冷和风隔绝开
04:09
So the water can stay
hidden in the ice sheet
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所以水得以隐藏在冰原之下
04:11
in liquid液体 form形成 year after year.
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以液态年复一年地存在着
04:14
The question is, what happens发生 next下一个?
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问题是 接下来会发生什么呢
04:17
Does the water stay there forever永远?
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那些水会永远待在那儿吗
04:19
It could.
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这是可能的
或者它能找到一种
流入全球海洋的方法吗
04:20
Or does it find a way out
to reach达到 the global全球 ocean海洋?
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04:24
One possible可能 way
for the water to reach达到 the bedrock基岩
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水要流到基岩并且
从那儿流入海洋的
04:27
and from there the ocean海洋
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一种可行方法
04:29
is a crevasse裂缝, or a crack裂纹 in the ice.
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是找到一个决口 或是冰里面的缝隙
04:32
When cracks裂缝 fill with water,
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当裂缝中充满了水
04:34
the weight重量 of the water
forces军队 them deeper更深 and deeper更深.
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水的重量使它们不断向下开裂
04:37
This is how fracking压裂 works作品
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这是液态破碎法的工作原理
04:39
to extract提取 natural自然 gas加油站
from deep within the earth地球.
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使地球深处的天然气流出
04:42
Pressurized加压 fluids流体 fracture断裂 rocks岩石.
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增压的流体使岩石破碎
04:44
All it takes is a crack裂纹 to get started开始.
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这一切只需要从一个裂缝开始
04:47
Well, we recently最近 discovered发现
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我们最近发现
04:50
that there are cracks裂缝 available可得到
in the Greenland格陵兰 ice sheet
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在格陵兰岛的冰原就有这样的裂缝
04:54
near this glacier冰川 aquifer含水层.
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在冰川含水层附近
04:56
You can fly over
most of the Greenland格陵兰 ice sheet
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你可以飞过格陵兰岛的大部分冰原
04:58
and see nothing,
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但你什么都看不到
04:59
no cracks裂缝, no features特征 on the surface表面,
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没有裂缝 表面也没有任何征兆
05:02
but as this helicopter直升机
flies苍蝇 towards the coast,
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但是当这架直升机飞向海岸
05:06
the path路径 that water would take
on its quest寻求 to flow downhill下坡,
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沿着水流下山的路径
05:09
one crack裂纹 appears出现,
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一个裂缝出现了
05:11
then another另一个 and another另一个.
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接着一个又一个
这些裂缝中都充满了液态水吗
05:14
Are these cracks裂缝 filled填充 with liquid液体 water?
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05:17
And if so, how deep
do they take that water?
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如果是的话 那些水有多深呢
05:20
Can they take it to the bedrock基岩
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它们深到基岩了吗
05:21
and the ocean海洋?
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或者是海洋
05:23
To answer回答 these questions问题,
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为了回答这些问题
05:24
we need something
beyond remote远程 sensing传感 data数据.
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我们需要一些遥感数据以外的信息
我们需要数学模型
05:28
We need numeric数字 models楷模.
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05:31
I write numeric数字 models楷模
that run on supercomputers超级计算机.
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我编写了一个在超型计算机上
运行的数学模型
05:34
A numeric数字 model模型
is simply只是 a set of equations方程
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一个数学模型只是一组方程式
05:36
that works作品 together一起 to describe描述 something.
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它们一起运作时可以描述一些东西
05:39
It can be as simple简单
as the next下一个 number in a sequence序列 --
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它可能和序列中下一个数字一样简单
05:42
one, three, five, seven --
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1 3 5 7
05:45
or it can be a more complex复杂
set of equations方程
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或者也可以是更复杂的方程组
05:47
that predict预测 the future未来
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基于现在
05:49
based基于 on known已知 conditions条件 in the present当下.
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已知的条件预测未来
05:51
In our case案件, what are
the equations方程 for how ice cracks裂缝?
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在我们的案例中描述
冰裂的方程式是什么呢
05:56
Well, engineers工程师 already已经 have
a very good understanding理解
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工程师已经熟知
05:59
of how aluminum, steel and plastics塑料
fracture断裂 under stress强调.
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关于铝 钢和塑料在压力下如何断裂
06:04
It's an important重要 problem问题 in our society社会.
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这对于我们的社会生活十分重要
06:07
And it turns out
that the engineering工程 equations方程
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事实证明 工程师关于材料如何断裂的
06:10
for how materials物料 fracture断裂
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数模方程
06:11
are not that different不同
from my physics物理 homework家庭作业.
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和我的物理作业没有什么不同
06:14
So I borrowed them, adapted适应 them for ice,
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所以我借鉴了它们 并运用到冰中
06:17
and then I had a numeric数字 model模型
for how a crevasse裂缝 can fracture断裂
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于是我建立了一个关于
当裂缝充满了来自含水层的水
06:20
when filled填充 with water from the aquifer含水层.
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会如何断裂的数学模型
06:24
This is the power功率 of math数学.
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这是数学的力量
06:25
It can help us understand理解
real真实 processes流程 in our world世界.
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它能帮我们了解这个世界中
一个个真实的过程
06:29
I'll show显示 you now
the results结果 of my numeric数字 model模型,
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我现在要向你们展示
我的数模计算结果
06:32
but first I should point out
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但是首先我要指出
06:34
that the crevasse裂缝 is about
a thousand times narrower than it is deep,
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这些决口的宽度
比它们的深度小1000倍
06:38
so in the main主要 panel面板 here,
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所以在这个主面板上
06:39
we've我们已经 zoomed放大 in to better see the details细节.
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我们放大了它以便更好地观察细节
06:41
You can look to the smaller
panel面板 on the right
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你们可以参考右边那个更小的数据条
来估算这些狭长裂缝的真实尺寸比例
06:43
to see the true真正 scale规模
for how tall and skinny枯瘦 the crevasse裂缝 is.
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06:48
As the aquifer含水层 water
flows流动 into the crevasse裂缝,
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因为含水层的水流入了裂缝
06:51
some of it refreezesrefreezes
in the negative 15 degree Celsius摄氏 ice.
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其中一部分在零下15摄氏度结冰了
06:55
That's about as cold
as your kitchen厨房 freezer冰箱.
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和厨房冰箱的冷冻层一样冷
06:57
But this loss失利 can be overcome克服
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但是这部分的缺失是可以克服的
06:59
if the flow rate in from
the glacier冰川 aquifer含水层 is high enough足够.
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如果来自含水层的流量足够大的话
07:03
In our case案件, it is,
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在我们的案例中情况就是这样的
07:05
and the aquifer含水层 water drives驱动器 the crevasse裂缝
all the way to the base基础 of the ice sheet
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含水层的水使裂缝裂到冰原的底部
07:09
a thousand meters below下面.
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海拔 负1000米
07:12
From there, it has a clear明确 path路径
to reach达到 the ocean海洋.
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在那儿 有一条很清晰的
通往海洋的路径
07:16
So the aquifer含水层 water is a part部分
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所以含水层的水部分影响了
07:18
of the three millimeters毫米
per year of sea level水平 rise上升
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每年海平面3毫米的上升
07:22
that we experience经验 as a global全球 society社会.
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这正是我们全球社会所经历的
07:26
But there's more:
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但是还有别的问题
07:27
the aquifer含水层 water
might威力 be punching冲孔 above以上 its weight重量.
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含水层的流量可能不足
07:31
The ice flows流动 in complex复杂 ways方法.
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冰以复杂的方式流动
07:35
In some places地方, the ice flows流动 very fast快速.
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在有的地方冰流动很快
07:37
There tends趋向 to be water
at the base基础 of the ice sheet here.
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它们可能在冰原的底部变成水
07:41
In other places地方, not so fast快速.
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在其他地方则没有这么快
07:43
Usually平时, there's not water
present当下 at the base基础 there.
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通常情况下在底部没有水的出现
07:46
Now that we know the aquifer含水层 water
is getting得到 to the base基础 of the ice sheet,
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既然我们知道了
含水层的水会到达冰原底部
07:50
the next下一个 question is:
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那么下一个问题是
07:52
Is it making制造 the ice itself本身
flow faster更快 into the ocean海洋?
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它会加快冰流入海洋的速度吗
07:58
We're trying to uncover揭露 these mysteries奥秘
hidden inside the Greenland格陵兰 ice sheet
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我们尝试着去解开
藏在格陵兰岛冰原下的秘密
08:01
so that we can better plan计划
for the sea level水平 rise上升 it holds持有.
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以便更好地规划解决
它所造成的海平面上升问题
08:06
The amount of ice
that Greenland格陵兰 has lost丢失 since以来 2002
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从2002年起格陵兰岛流失的冰量
08:09
is just a small fraction分数
of what that ice sheet holds持有.
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只是那片冰原体积的一小部分
08:14
Ice sheets床单 are immense巨大, powerful强大 machines
that operate操作 on long timescales时间表.
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冰原是巨型 强大
可以长时间工作的调节器
08:19
In the next下一个 80 years年份, global全球 sea levels水平
will rise上升 at least最小 20 centimeters公分,
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在未来的80年
全球海平面至少会上升20cm
08:24
perhaps也许 as much as one meter仪表,
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甚至可能是1米
08:26
and maybe more.
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也有可能更多
08:28
Our understanding理解
of future未来 sea level水平 rise上升 is good,
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我们对于未来海平面的了解是好的
08:31
but our projections预测 have a wide range范围.
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但是我们的预测太宽泛了
08:34
It's our role角色 as glaciologists冰川学家
and scientists科学家们
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我们作为冰川学家和
科学家的责任就是
08:37
to narrow狭窄 these uncertainties不确定性.
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减少这些不确定性
08:40
How much sea level水平 rise上升 is coming未来,
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海平面会上涨多少
08:43
and how fast快速 will it get here?
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上涨多快
08:46
We need to know how much and how fast快速,
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我们需要知道它的变化幅度和速度
08:50
so the world世界 and its communities社区 can
plan计划 for the sea level水平 rise上升 that's coming未来.
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这样社会各界才能做好准备
应对未来的海平面上升
08:55
Thank you.
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谢谢
(掌声)
08:56
(Applause掌声)
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Translated by Chen Yunru

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ABOUT THE SPEAKER
Kristin Poinar - Glaciologist
Kristin Poinar uses remote sensing and numerical models to study the interaction of meltwater with ice flow, especially on the Greenland Ice Sheet.

Why you should listen

Hidden under many meters of ice, a pool of meltwater lies under the Greenland Ice Sheet. Kristin Poinar studies how the meltwater forms and flows in this dynamic glacial system. She asks: How did this water get there, and where does it go? How much water is in there? And how is climate change affecting this system?

Using data from Operation IceBridge flights and from field instruments, she's building a numerical model of how crevasses form and channel water. In fact, a NASA report released in February 2017 revealed a new pathway her team discovered for meltwater to reach the ocean. Using physically based models to constrain the bounds of what is realistic has shaped Poinar's interest in glaciology.

Poinar is currently a postdoctoral researcher at NASA Goddard Space Flight Center. She will be moving to the University at Buffalo in winter 2017 to be a professor in the Geology Department and the RENEW Institute.

More profile about the speaker
Kristin Poinar | Speaker | TED.com