VOA标准英语2010-Climate Hastened Collapse of Angkor, Capi

Scientist uses tree rings to reconstruct 13th century climate

Art Chimes | Washington, DC 05 April 2010

 
Photo: Photos.com

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Angkor paper (full text)
Buckley lab
"We started seeing these big, giant periods of drought that took place around that time. And ... I realized that that was the time of the collapse¹ of Angkor."

 

For hundreds of years the Khmer empire ruled in what is now Cambodia.

But in the 13th century, the capital city, Angkor, died off, and a new scientific study indicates that climate, specifically decades of drought interspersed² with intense monsoons³, helped bring down the Khmer capital.

In the ancient world, Angkor was known for its sophisticated water system.

"Angkor was really the dominant⁴ civilization in that part of the world without any question," said Brendan Buckley, the Columbia University scientist who led the study.

"It was the center of their universe. And it was called the 'hydraulic⁵ city' because it had really remarkably⁶ massive arrays of barays, which are these giant water tanks and a series of canals and interconnected waterways that was really unparalleled in the ancient world in that part of the world."

Buckley isn't an archaeologist. He studies tree rings, which record the growth history of trees that can be hundreds of years old, or even older. A new ring is added every year, and thicker rings represent a kind of savings⁷ account, when the tree collects more nutrients⁸ than it can use. Thin rings show the tree is barely getting along, like during a drought year.

Using samples from around Southeast Asia, Buckley and his colleagues saw this pattern in tree rings from recent years, when he could corroborate⁹ the rings with other historical climate information. His newest tree ring samples, from the rare Fokienia hodginsii cypress¹⁰ in southern Vietnam, enabled him to take the climate record back much further.

"We realized we have trees that are more than 1,000 years old. And we started seeing these big, giant periods of drought that took place around that time. And as I started to get more interested in the history of Southeast Asia, I realized that that was the time of the collapse of Angkor."

The research team used what are called core samples from hundreds of trees throughout Southeast Asia. Using a hollow tube, they drill into the tree and extract a 5-mm wide cylinder¹¹ that shows each ring starting with the most recent, just under the bark.

By comparing rings from different trees and with other historical data, you can often identify particular rings with the exact calendar year that they grew.

"We were able to match up the narrow and wide rings exactly so that we can assign the exact calendar dates to the exact rings of every tree," Buckley explained. "In the tropics, a lot of tree species don't even form rings that we can see. So to be able to get a tree that, first of all, has very clear rings that we're able to visually match to each other and then go through and produce these long records was remarkable¹²."
 

1 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

2 interspersed   

adj.[医]散开的；点缀的v.intersperse的过去式和过去分词

参考例句：

• Lectures will be interspersed with practical demonstrations. 讲课中将不时插入实际示范。
• The grass was interspersed with beds of flowers. 草地上点缀着许多花坛。 来自《现代英汉综合大词典》

3 monsoons   

n.（南亚、尤指印度洋的）季风( monsoon的名词复数 )；（与季风相伴的）雨季；（南亚地区的）雨季

参考例句：

• In Ban-gladesh, the monsoons have started. 在孟加拉，雨季已经开始了。 来自辞典例句
• The coastline significantly influences the monsoons in two other respects. 海岸线在另外两个方面大大地影响季风。 来自辞典例句

4 dominant   

adj.支配的，统治的；占优势的；显性的；n.主因，要素，主要的人(或物)；显性基因

参考例句：

• The British were formerly dominant in India.英国人从前统治印度。
• She was a dominant figure in the French film industry.她在法国电影界是个举足轻重的人物。

5 hydraulic   

adj.水力的；水压的，液压的；水力学的

参考例句：

• The boat has no fewer than five hydraulic pumps.这艘船配有不少于5个液压泵。
• A group of apprentics were operating the hydraulic press.一群学徒正在开动水压机。

6 remarkably   

ad.不同寻常地，相当地

参考例句：

• I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
• He made a remarkably swift recovery. 他康复得相当快。

7 savings   

n.存款，储蓄

参考例句：

• I can't afford the vacation,for it would eat up my savings.我度不起假，那样会把我的积蓄用光的。
• By this time he had used up all his savings.到这时，他的存款已全部用完。

8 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

9 corroborate   

v.支持，证实，确定

参考例句：

• He looked at me anxiously,as if he hoped I'd corroborate this.他神色不安地看着我，仿佛他希望我证实地的话。
• It appeared that what he said went to corroborate my account.看来他所说的和我叙述的相符。

10 cypress   

n.柏树

参考例句：

• The towering pine and cypress trees defy frost and snow.松柏参天傲霜雪。
• The pine and the cypress remain green all the year round.苍松翠柏，常绿不凋。

11 cylinder   

n.圆筒，柱(面)，汽缸

参考例句：

• What's the volume of this cylinder?这个圆筒的体积有多少？
• The cylinder is getting too much gas and not enough air.汽缸里汽油太多而空气不足。

12 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。