VOA标准英语2012--Mapping Mountain Range Found Under Antarctic Ice

Mapping Mountain Range Found Under Antarctic Ice

It’s late afternoon at the Lamont-Doherty Earth Observatory¹, where Robin² Bell is at work analyzing³ various images of glaciers⁴ and plotting her next expedition to the frozen southern pole. She takes a break to explain why she loves ice so much.
“Ice is cool because it is really hard to look under. So there are all kinds of mysteries that are underneath⁵ the ice sheet that you can’t see without sending out radar⁶ energy. You get to look somewhere nobody has looked before. So you get to find things that nobody had thought about before.”
Hidden wonder
Such as an entire mountain range, hidden from view beneath a sheet of ice several kilometers thick.
“We went to the middle of the Eastern Antarctica ice sheet, which the biggest one on the planet. It covers the entire eastern half of Antarctica. The top of the ice sheet is about 4,200 meters high (above sea level) and underneath that is a mountain range. The Russians discovered the mountain range when they drove across it in 1958, and they found the ice was really thin there. But nobody had been back there, pretty much, in the following 50 years.”
There is no visible evidence of these peaks and valleys beneath the unbroken surface of the ice field, and Bell was determined⁷ to learn more about them.
In 2008, she outfitted⁸ a small plane with sensitive laser, radar and magnetic-field monitoring equipment, and oversaw⁹ a series of systematic¹⁰ aerial surveys over the ice sheet. The resulting images, which look very much like dental X-rays, showed the mountains, and more.
Closer look
“There were things that looked more like clouds or mushrooms or something at the bottom of the ice sheet. But big! Like a kilometer thick. So, being a scientist, first you think there is something wrong with your instruments, because there shouldn’t be things that look like this under the ice sheet. But when you start seeing it on one line and then five kilometers later you see it on the next line and then the next one you begin to think ‘there might actually be something there.’”
What Bell was seeing was an entire range of mountains, more like the Alps than the scattered¹¹ “mega-bumps” she and her team expected to find. There were also valleys and, at the base of the mountains, four kilometers underground, rivers of slow-moving water.
“When we go to the middle of Antarctica, the average temperature is roughly minus-40 degrees Centigrade (Celsius). That’s at the surface. But the ice sheet acts like a blanket and captures the heat of the earth coming up. So the bottom of the ice sheet is only about minus two degrees Centigrade. So it’s not very far from melting. It’s pretty warm down there.”
Bell and her team found other surprises in this hidden, ice-blanketed world, such as rivers that flowed uphill.
“We really hadn’t thought about what would happen to water and valleys when you drop a four and a half kilometer thick ice sheet on top of it and that you’d actually end up driving the water up the hill. Because the ice is thinner at the end of the valley than down at the bottom. So the water is actually getting squirted uphill.”
Revamping impressions
The discovery that liquid water is flowing beneath Antarctica’s massive ice sheet has forced scientists to revise their view of the so-called “frozen continent.” It was long believed that the ice sheet was layered like a birthday cake, with the newest ice near the top, where the most recent snowfalls had frozen.
But Bell says it now seems that some of the most ancient ice is being melted and then pressed uphill by the weight of the ice above it, until it freezes again. That means many ice layers higher up in the ice sheet might actually be more ancient than the layers below them.
“Which is a kind of a backwards¹² way of thinking about things.”
Bell says her research might seem exotic but its implications are urgent.
“If we want to know how the ice sheets are going to change in the future, we need to know how they are going to move. And they move on their bottoms. So what the bottom of the ice sheet is made of really matters.”
Bell believes her work at Columbia University’s Lamont-Doherty Earth Observatory is doing more than deepening our understanding of the physics of polar ice.
Bell says that knowing why and how that ice melts will also help scientists better predict the effects of global climate change, and the profound environmental impacts it is certain to have.

1 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

2 robin   

n.知更鸟，红襟鸟

参考例句：

• The robin is the messenger of spring.知更鸟是报春的使者。
• We knew spring was coming as we had seen a robin.我们看见了一只知更鸟，知道春天要到了。

3 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句

4 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

5 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

6 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

7 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

8 outfitted   

v.装备，配置设备，供给服装( outfit的过去式和过去分词 )

参考例句：

• They outfitted for the long journey. 他们为远途旅行准备装束。 来自《现代英汉综合大词典》
• They outfitted him with artificial legs. 他们为他安了假腿。 来自辞典例句

9 oversaw   

v.监督，监视( oversee的过去式 )

参考例句：

• He will go down as the president who oversaw two historic transitions. 他将作为见证了巴西两次历史性转变的总统，安然引退。 来自互联网
• Dixon oversaw the project as creative director of Design Research Studio. 狄克逊监督项目的创意总监设计研究工作室。 来自互联网

10 systematic   

adj.有系统的，有计划的，有方法的

参考例句：

• The way he works isn't very systematic.他的工作不是很有条理。
• The teacher made a systematic work of teaching.这个教师进行系统的教学工作。

11 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

12 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。