题型:完形填空 题类:常考题 难易度:困难
上海市杨浦区2021届高三上学期英语期中试卷
Trackers on Ice
Just because a scientist puts a GPS tracking collar on a wild polar bear does not mean the animal will willingly keep it on. 1, these huge collars are purposefully loose so that if one becomes annoying, a bear can 2it. But scientists have now found a way to use signals from the discarded(丢弃的)devices.
"These dropped collars3would have been considered garbage data," says Natasha Klappstein, a polar bear researcher at the University of Alberta. She and her colleagues instead used4from such collars, left on sea ice in Canada's Hudson Bay, to track the ice itself. For their study, published in June in The Cryosphere, the researchers 5twenty collars that sent movement data consistent(与······一致的)with ice drift rather than polar bear 6between 2005 and 2015. The resulting records of how melting ice typically drifts in Hudson Bay are unique; there are no easily 7on-the-ground sensors, and satellite observations often cannot 8capture the motion of small ice sheets.
The team compared the discarded collars' movements with 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 9of drift. Over the course of several months the model could drift away from an ice sheet's location by a few hundred kilometers, the researchers say.
This means the bears may be working harder, when moving against the direction of the ice, than scientists had 10 ."Since we're underestimating the speed of drift, we're likely underestimating the energetic effort of polar bears," says Natasha Klappstein. The research reveals11insight (洞悉) into how highly mobile ice moves. As melting increases in coming years, such ice will likely become more 12farther north, in the central Arctic. Scientists had known NSIDC data could underestimate drift speeds, but "any time we can find a data 13, it is a good thing."
Plus, such data could improve predictions about how oil spills or other pollutants may spread in seas 14 with drifting ice, says Walt Meier, a senior NSIDC research scientist, who was not involved in the study. The findings may even 15future NSIDC models. "It's a really nice data set," Meier says." And certainly one we'll take consideration.
试题篮