PBS高端访谈:科学家根据阿拉斯加冰雪层的状况监测气候变化

 　　GWEN IFILL: Finally tonight: how climate change may be affecting life in Alaska as we know it and the captivating images we see there, from ice to Marine¹ life.

　　NewsHour science correspondent Miles O'Brien went there to see for himself.

　　MILES O'BRIEN: Alaska may seem like a place where things don't change very quickly, the natural beauty is set in stone and is as predictable as the caribou² beside the road.

　　But make no mistake, things are changing here quickly, and not for the better. Alaska is at the frontier of climate change. Scientists are scrambling³ to try and understand it.

　　KARL KREUTZ, University of Maine: We know that the Arctic is warming more rapidly than most other places on Earth.

　　MILES O'BRIEN: To catch up with University of Maine paleoclimatologist Karl Kreutz and his team, we hopped⁴ on a plane rigged with skis that landed right on the Ruth Glacier⁵ in the heart of the Denali National Park.

　　KARL KREUTZ: Most glaciers⁶ in Alaska are retreating. We'd like to be able to predict with better accuracy of what will happen, but it's hard to imagine a scenario⁷ there where glaciers will not continue to lose mass in this area. The question is how fast.

　　MILES O'BRIEN: But the answer is unknowable if they don't know how much ice is here right now.

　　SETH CAMPBELL, U.S. Army Corps⁸ of Engineers: To goal of this specific study is to come up with ice depth measurement across the glacier.

　　MILES O'BRIEN: Kreutz's colleague Seth Campbell is a research geophysicist for the U.S. Army Corps of Engineers. He and University of Maine undergrad Abby Bradford spent long, strenuous⁹ days on skis towing a ground-penetrating radar¹⁰ up, down and across the glacier.

　　SETH CAMPBELL: The transfer sends a pulse through the cable. The pulse gets sent down through the ice, reflects off the bedrock, returns back to the surface. And it returns and is recorded by this receiver cable.

　　We know how fast a radio wave travels through the ice, so based on how long it takes it for the signal to be transmitted and received, we can calculate how deep the ice is.

　　All right, so sample two should come from a depth of 50 centimeters, please.

　　MILES O'BRIEN: To have complete confidence in the radar data, they dug this pit 11.5-feet deep and had Abby repel¹¹ down to take readings.

　　MAN: This is great. SEAL Team Six time. Let's go, baby!

　　MILES O'BRIEN: Dutiful reporter that I am, I went in.

　　ABIGAIL BRADFORD, University of Maine: So what we're in, this is just one layer, one annual layer. This is this year's snowfall. And then right what we're standing¹² on, where this probe stops — it's a bit covered with snow now, but there's an ice layer right there.

　　MILES O'BRIEN: And you know that's the previous season?

　　ABIGAIL BRADFORD: That's the previous season, yes.

　　MILES O'BRIEN: She weighs a fixed¹³ volume of snow at various depths to determine its density¹⁴. The hope is the layering they see in the pit matches the radar returns.

　　ABIGAIL BRADFORD: There's thousands of glaciers in Alaska, and very few have had data gathered on them. So we're hoping to piece that puzzle together.

　　MILES O'BRIEN: Getting back to the surface might have been easy for her, but, for me, well, let's just say I didn't score any style points.

　　Later in camp, Karl Kreutz dug me a shallower pit.

　　KARL KREUTZ: But, of course, as we're going deeper in this — on this wall, we're going back in time.

　　MILES O'BRIEN: A thin wall backlit by the sun. The key is the layers of snow and most importantly ice, proof of a melt.

　　KARL KREUTZ: These layers in the snowpack are very analogous¹⁵ to tree rings. All of these, as we go down and go through the layers are going back in time on the glacier, and we get deeper and deeper.

　　MILES O'BRIEN: Last season, they went much deeper, drilling out this long ice core a few miles away. It is nature's ancient history book for this glacier.

　　KARL KREUTZ: So, over the past 40 or 50 years, the number of ice layers that have formed each summer has been increasing. And so we interpret that as meaning that the summertime temperatures in this area have gradually been warming over the past couple decades.

　　MILES O'BRIEN: The vast majority of glacier ice on our planet lies in Greenland and Antarctica, and so it should come as no surprise that's where most of the attention and scientific effort is.

　　But the people who come here to the mountains and the glaciers say the ice here shouldn't be overlooked.

　　SETH CAMPBELL: The interesting thing about Alaska is, a lot of the glaciers sit right at a temperature — right at a zero degree temperature. So, small changes in atmospheric¹⁶ air temperature can cause drastic changes in ice point.

　　MILES O'BRIEN: Five hundred and fifty miles north on the sea ice off Barrow, the notion that Alaska rocks at a tipple¹⁷ point is not just academic. It's a matter of survival for a proud culture.

　　The 2005 film "The Eskimo and the Whale" tells the story of the Inupiat people trying to preserve their subsistence whale hunting tradition.

　　NELSON NUNGASAT, Inupiat Whaler: The ice is shrinking. We have a lot of cracks in the ice, so we have to watch them a lot more. When I was little, these — these ice piles here, they were — they were 10 times bigger.

　　MILES O'BRIEN: Nelson Nungasat is captain of a whale hunting team. They rely on stable, thick ice to harpoon¹⁸ the 25 bowhead whales they're allowed to take each year for food.

　　Nelson works as a guide and polar bear sentinel for some scientists focused on the sea ice and the other end of the food chain, the tiny light-sensitive organisms that live in the ice.

　　CRAIG AUMACK, Columbia University: Temperatures effects up here and ice extent up here actually has profound effects on the marine community underneath¹⁹ the ice.

　　MILES O'BRIEN: Marine ecologist Craig Aumack is with Columbia University's Lamont-Doherty Observatory²⁰. He and his team do a lot of coring as well to measure the temperature of the ice at 10-centimeter intervals²¹. They drop cameras through the holes and take a peek²² underneath.

　　What do you hope to see?

　　CRAIG AUMACK: Well, we kind of just look at the bottom to see. So that pigmentation, this is all algae²³.

　　MILES O'BRIEN: During the winter, the algae hibernates²⁴ in the ice, but, in the spring, it blooms and drops into the water. When and how fast that happens depends on how much light gets through the ice. And that is changing as the ice shrinks, gets thinner and is covered by less snow.

　　CRAIG AUMACK: So what we're really interested in is then finding out what role this material plays in the total diet of these organisms.

　　It's really hard to understand the impact of the loss of sea ice without actually understanding then what importance it has toward the underlying²⁵ marine systems.

　　MILES O'BRIEN: Algae is a so-called primary producer, meaning it is foundation for the entire food chain.

　　Craig's scientific collaborator²⁶ is marine biologist Andy Juhl.

　　ANDY JUHL, Columbia University: We know it starts out in the ice, it grows in the ice. Then it gets released from the ice. It ends up in the water. Some of it sinks to the bottom. And so the next question is, who's eating it?

　　MILES O'BRIEN: They analyze²⁷ all manner of small creatures to see what they're eating and, by analyzing²⁸ their tissue, what provides them the most nutrition. As they gather data, they are working their way up the chain. On this day, they netted a jellyfish.

　　MAN: Jelly.

　　MILES O'BRIEN: Cause enough for a science nerd happy dance on the ice. But beneath the surface here, there are grave concerns about what happens when the sea ice is dramatically diminished.

　　ANDY JUHL: Large marine animals, seals and beluga whales and bowhead whales, the polar bears, all of those organisms are here, because it is an incredibly productive environment and therefore can support those really big organisms, because there are a lot of algae at the base of the food chain here.

　　MILES O'BRIEN: The amount of snowfall, the depth of the ice supports a finely-honed balance that ultimately sustains the top of the food chain. Here, a single degree of change across the line between ice and water is changing everything.

　　Miles O'Brien, the "PBS NewsHour," Barrow, Alaska.

1 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

2 caribou   

n.北美驯鹿

参考例句：

• Afar off he heard the squawking of caribou calves.他听到远处有一群小驯鹿尖叫的声音。
• The Eskimos played soccer on ice and used balls filled with caribou hair and grass.爱斯基摩人在冰上踢球，他们用的是驯鹿的毛发和草填充成的球。

3 scrambling   

v.快速爬行( scramble的现在分词 )；攀登；争夺；（军事飞机）紧急起飞

参考例句：

• Scrambling up her hair, she darted out of the house. 她匆忙扎起头发，冲出房去。 来自《现代英汉综合大词典》
• She is scrambling eggs. 她正在炒蛋。 来自《简明英汉词典》

4 hopped   

跳上[下]( hop的过去式和过去分词 )； 单足蹦跳； 齐足（或双足）跳行； 摘葎草花

参考例句：

• He hopped onto a car and wanted to drive to town. 他跳上汽车想开向市区。
• He hopped into a car and drove to town. 他跳进汽车，向市区开去。

5 glacier   

n.冰川，冰河

参考例句：

• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。
• The upper surface of glacier is riven by crevasses.冰川的上表面已裂成冰隙。

6 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）

7 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。

8 corps   

n.(通信等兵种的)部队；(同类作的)一组

参考例句：

• The medical corps were cited for bravery in combat.医疗队由于在战场上的英勇表现而受嘉奖。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

9 strenuous   

adj.奋发的，使劲的；紧张的；热烈的，狂热的

参考例句：

• He made strenuous efforts to improve his reading. 他奋发努力提高阅读能力。
• You may run yourself down in this strenuous week.你可能会在这紧张的一周透支掉自己。

10 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。

11 repel   

v.击退，抵制，拒绝，排斥

参考例句：

• A country must have the will to repel any invader.一个国家得有决心击退任何入侵者。
• Particles with similar electric charges repel each other.电荷同性的分子互相排斥。

12 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

13 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

14 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

15 analogous   

adj.相似的；类似的

参考例句：

• The two situations are roughly analogous.两种情況大致相似。
• The company is in a position closely analogous to that of its main rival.该公司与主要竞争对手的处境极为相似。

16 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

17 tipple   

n.常喝的酒；v.不断喝，饮烈酒

参考例句：

• My favourite tipple is a glass of port.我最喜欢喝的酒是波尔图葡萄酒。
• Scotch drinkers around the world tend to associate their favourite tipple with success and achievement.世界各地喝苏格兰威士忌的人，往往把他们最喜欢的这种烈酒，与成功和成就联系在一起。

18 harpoon   

n.鱼叉；vt.用鱼叉叉，用鱼叉捕获

参考例句：

• The harpoon drove deep into the body of the whale.渔叉深深地扎进鲸鱼体内。
• The fisherman transfixed the shark with a harpoon.渔夫用鱼叉刺住鲨鱼。

19 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。

20 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。

21 intervals   

n.[军事]间隔( interval的名词复数 )；间隔时间；[数学]区间；（戏剧、电影或音乐会的）幕间休息

参考例句：

• The forecast said there would be sunny intervals and showers. 预报间晴，有阵雨。
• Meetings take place at fortnightly intervals. 每两周开一次会。

22 peek   

vi.偷看，窥视；n.偷偷的一看，一瞥

参考例句：

• Larry takes a peek out of the window.赖瑞往窗外偷看了一下。
• Cover your eyes and don't peek.捂上眼睛，别偷看。

23 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。

24 hibernates   

（某些动物）冬眠，蛰伏( hibernate的第三人称单数 )

参考例句：

• The turtle hibernates in a shallow burrow for six months of the year. 海龟一年在一个浅洞中冬眠六个月。
• PC hibernates and wakes up from hibernation properly. PC休眠和唤醒都正常了。

25 underlying   

adj.在下面的，含蓄的，潜在的

参考例句：

• The underlying theme of the novel is very serious.小说隐含的主题是十分严肃的。
• This word has its underlying meaning.这个单词有它潜在的含义。

26 collaborator   

n.合作者，协作者

参考例句：

• I need a collaborator to help me. 我需要个人跟我合作，帮我的忙。
• His collaborator, Hooke, was of a different opinion. 他的合作者霍克持有不同的看法。

27 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。

28 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