Just because a scientist puts a GPS tracking collar on a wild polar bear does not mean the animal will willingly keep it on. They can remove it, if one becomes annoying. But scientists have now found a way of using signals from those dropped collars to track the ice itself.
The scientists identified 20 collars that transmitted movement data consistent with ice drift ( 漂流 ) rather than polar bear motion between 2005 and 2015. The resulting records of how melting ice drifts in Hudson Bay are unique; there are no easily accessible on-the-ground sensors, and satellite observations often cannot accurately capture the motion of small ice sheets.
The team compared the removed collars’ movements to widely used ice-drift modeling data from the U. S. National Snow and Ice Data Center (NSIDC). Collar data indicated that the NSIDC model underestimates the speed at which ice moves around in Hudson Bay — as well as the overall extent of drift. Over the course of several months the model could diverge ( 偏离 ) from an ice sheet’s location by a few hundred kilometers, the scientists say.
This means the bears may be working harder, when moving against the direction of the ice, than scientists had assumed, “Since we’re underestimating the speed of drift, we’re likely underestimating the energetic effort of polar bears,” says Ron Togunov, who led the study.
The study reveals timely insight into how highly mobile ice moves. As melting increases in coming years, such ice will likely become more common farther north, in the central Arctic, says Andy Mahoney, a geophysicist at the University of Alaska, who was not involved in the study. Scientists had known NSIDC data could underestimate drift speeds, Mahoney says, but “any time we can find a data gap and plug it is a good thing.”
Plus, such data could improve predictions about how oil spills or other pollutants may spread in seas littered with drifting ice, says Walt Meier, a senior NSIDC research scientist. The findings may even influence future NSIDC models. “It'’s a really nice data set.” Meier says. “And certainly one we’ll take under consideration.”
1 . What can a GPS tracking collar do?
A . Measure the depth of ice sheet. B . Capture the movement of ice.
C . Describe the melting speed of ice. D . Record the emotional state of bears.
2 . What can we learn about the collar data?
A . It shows the ice moves more slowly from its original location.
B . It may reveal polar bears are not so energetic as before.
C . It indicates the ice is more likely to move south in the central Arctic.
D . It can help predict the location of some pollutants in seas.
3 . Which would be the best title for this passage?
A . Data Tells a Different Story B . Wild Polar Bears’ Signaling
C . Insights into a Puzzling Aspect D . Ice Is Taken under Consideration
1 . B
2 . D
3 . A
【分析】
这是一篇说明文。文章主要介绍了 GPS 跟踪项圈能捕获冰层的运动,让我们对冰层移动的速度以及漂移的总体范围有了新的认知。
1 .细节理解题。根据第一段关键句 “But scientists have now found a way of using signals from those dropped collars to track the ice itself.( 但是科学家们现在发现了一种方法,可以利用掉下来的项圈发出的信号来追踪冰层本身 )” 和第二段关键句 “The scientists identified 20 collars that transmitted movement data consistent with ice drift ( 漂流 ) rather than polar bear motion between 2005 and 2015.( 科学家们发现了 20 个项圈,这些项圈传递的运动数据与 2005 年至 2015 年间的冰层漂流一致,而不是北极熊的运动 )” 可知,这些掉下来的 GPS 跟踪项圈可以发出信号来追踪冰层本身,能够传递冰层运动的数据。由此可知, GPS 跟踪项圈能捕获冰的运动。故选 B 项。
2 .细节理解题。根据最后一段关键句 “Plus, such data could improve predictions about how oil spills or other pollutants may spread in seas littered with drifting ice, says Walt Meier, a senior NSIDC research scientist.( 此外, NSIDC 的一位高级研究科学家 Walt Meier 说,这样的数据可以改进关于溢油或其他污染物如何在布满浮冰的海洋中扩散的预测 )” 可知, GPS 跟踪项圈捕获的数据可以帮助预测海洋中一些污染物的位置。故选 D 项。
3 .主旨大意题。分析文章内容,结合第三段关键句 “The team compared the removed collars’ movements to widely used ice-drift modeling data from the U. S. National Snow and Ice Data Center (NSIDC). Collar data indicated that the NSIDC model underestimates the speed at which ice moves around in Hudson Bay — as well as the overall extent of drift.( 研究小组将移除的项圈的运动与美国国家冰雪数据中心( NSIDC )广泛使用的冰漂移建模数据进行了比较。项圈数据表明, NSIDC 模型低估了哈德逊湾冰层移动的速度以及漂移的总体范围 )” 可知, GPS 跟踪项圈捕获的数据与 NSIDC 模型的数据不相符,让我们对冰层移动的速度以及漂移的总体范围有了新的认知。 “Data Tells a Different Story” 意为 “ 数据说明了另一种情况 ” 能够概括文章主要内容。故选 A 项。