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南极冰架坍塌加速冰河流动

双击单词可弹出解释框  时间:2010-07-16 21:51  作者:

  
 
 
Accelerating glaciers contribute to raised sea levels。
 
 
The impact of climate change on the Antarctic Peninsula is evident in new satellite data, US researchers say.

The collapse of the Larsen B ice shelf two years ago has accelerated the flow of glaciers into the nearby Weddell Sea

It is probable the disintegration in 2002 has now allowed the glaciers to deposit their loads more freely, the team tells Geophysical Research Letters

The Antarctic Peninsula has seen some of the fastest temperature rises on Earth in the last five decades.

The scientists used a variety of data from satellites to track the speed of the glaciers before and after the collapse of Larsen B.

In one study, Ted Scambos of the National Snow and Ice Data Center in Boulder, US, analysed five images taken by the Landsat 7 satellite between January 2000 and February 2003.

The analysis reveals that four glaciers flowing into the now collapsed section of Larsen B increased in speed by between two and six times over the study period.

"If anyone was waiting to find out whether Antarctica would respond quickly to climate warming, I think the answer is yes," said Dr Scambos.

The second report, by Eric Rignot of the US space agency's Jet Propulsion Laboratory in Pasadena, US, showed an eightfold increase in the speed of three glaciers, called Hektoria, Green and Evans, between 2000 and 2003.

Two others, Jorum and Crane, moved twice as quickly at the beginning of 2003 than they did in 2000 and nearly three times as fast by the end of the year.

"These two papers clearly illustrate, for the first time, the relationship between ice shelf collapses caused by climate warming, and accelerated glacier flow," said Dr Rignot.

The extra ice presumably translates into higher sea level. But how much this is raising the level of the oceans isn't known.

The authors of the published papers point out that in other places around the continent, much larger glaciers are also held in check by ice shelves.

The Antarctic Peninsula is one of the three fastest-warming regions on Earth - temperatures have risen 2.5 degrees in 50 years.

But the picture generally in Antarctica is complicated, with temperatures in the interior actually falling over the same period.

There is also some evidence that the retreat of the West Antarctic ice sheet, on the other side of the peninsula to the Larsen B shelf, has halted.   
 

 美国研究者表示,卫星传回的新数据显示,南极半岛的气候变化带来了显著的影响。

 

两年前崩塌的“守护神B”冰架(巨大的浮动冰层)加快了冰河流入附近的威德尔海的速度。

 

研究小组对《地球物理研究快报》(Geophysical Research Letters)表示,可能是因为2002年的冰架解体才使得冰河更容易地聚集了能量。

 

过去的五十年间,南极半岛是地球上气温升高最快的地区之一。

 

科学家们使用卫星发回的各种数据来研究"守护神B"冰架崩塌之前和之后冰河流动的速度。

 

在一项研究中,美国国家冰雪数据中心(位于博尔德市)的特德·斯坎博斯对美国地球资源探测卫星7号在2000年1月和2003年2月之间拍摄的五幅图像进行了分析。

分析表明,四条流入“守护神B”冰架现已崩塌部分的冰河在研究期间的流速增加了2至6倍。

斯坎博斯博士说:“如果有人想知道气候变暖是否很快会对南极洲产生影响,我想答案是肯定的。”


埃里克·里戈诺特供职于美国国家航空航天局设在帕萨迪纳市的喷气推进实验室,他所做的第二份报告显示,2000年到2003年间三条分别名为黑克多利亚、格林和埃文斯的冰河的流速增加了8倍。

另外两条分别名为乔洛姆和克莱恩的冰河在2003年初的流速比2000年增加了一倍,到2003年年底,流速几乎增加到原来的3倍。

里戈诺特博士说:“这两份报告第一次清楚地说明了气候变暖导致的冰架崩塌与冰河流速加快之间的关系。”

可以推测,(冰架崩塌产生的)多余的冰块会使海平面高度进一步上升,但上升的程度目前尚不可知。

发表上述论文的作者们指出,在南极大陆的其他地区,还有更大的冰河正处在冰架的包围和阻挡中。

南极半岛是地球上温度升高最快的三个地区之一,其气温在50年间上升了2.5 摄氏度。

但是南极洲的总体情况却很复杂,在因为同一时期内,该地区的地下温度实际上降低了。

还有一些证据显示,与“守护神B”冰架隔南极半岛相望的西南极洲大冰原已经停止了后退。 

 
  
 
 
Vocabulary:

 
ice shelf : ice that is attached to land but projects out to sea(冰架)

glacier: a huge mass of ice slowly flowing over a land mass, formed from compacted snow in an area where snow accumulation exceeds melting and sublimation(冰河、冰川)

 


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