From
VOA Learning English, this is Science in the News.
I’m Christopher Cruise.
And I’m Kelly Jean Kelly.
And I’m Kelly Jean Kelly.
Today we tell about summer1 ice loss2 in parts of Antarctica.
We also tell how unrest3 in Egypt has hurt4 the
country’s travel industry. But it has led to5 the return of
the scientist formerly6
responsible for the famous pyramids. And we report on
the recent Microsoft magine Cup, a technology competition for students.
Scientists are learning new things about7 Antarctica, the coldest place on Earth8. For example, the Antarctic ice sheet9 is shrinking10. A new study found that summer ice loss in parts of Antarctica was at its highest level11 in 1,000 years. The study showed that Antarctic ice was melting12 mostly13 from below14 iceshelves15, where the water is warmer than16 the ice.
Ice shelves are the floating edges17 of the ice sheet – the ice cover18 - that extend over19 ocean waters. The study is the first complete look at all of the continent’s ice shelves.
Eric Rignot is an earth20 system expert at the University of California, Irvine. He also works for the American space agency,NASA. There he serves as senior research scientist21 at NASA’s Jet Propulsion Laboratory22, also in California.
He says ice melting from below is responsible for 55 percent of the shelf loss from 2003 to 2008. That is a much higher rate23 than scientists thought24 earlier25.
“We find that the melting of the underside26 of the ice shelves is even larger than27 the production of icebergs. So it is the dominant process of mass28 removal29 in the Antarctic.”
Professor Rignot and his team used satellite observations, radar and computer models to measure features30 above the ice to learn what was going on31 below.
“That includes the velocity of the ice, the thickness32 of the ice, how fast33 the “freeboard” (height34 of ice above sea level35) of the iceshelf is changing with time and also how much snowfall36 there is on the top of the ice shelves.”
The measurements37 show differences from one area to the next38 around the continent. The major ice shelves are called Ross, Filchner and Ronne. They make up two-thirds39 of Antarctica’s ice shelves. But they are responsible for only 15 percent of the melting ice.
At the same time40, about41 ten smaller ice shelves produced half the total water from ice melting during42 the same period. The smaller ones43 are found along the edges44 of comparatively warm water. Professor Rignot describes45 the importance of the information.
“That means46 that during warming47 of the climate where the properties48 of the Southern Ocean are changing, they may be changing faster than49 other oceans in the world. We may be in a situation where the coastline50 of Antarctica may be changing at a faster pace51 than we thought in the past.”
The professor says even small changes, like changes in ocean flow52 driven by wind53, can make a huge54 difference in the melting of the ice shelf.
“If the wind regime changes in the Southern Ocean, it is going to change the way the ocean heat55 is distributed on the coast. And that’s going to affect glaciers56.”
Sixty percent of the Earth’s fresh water57 is held in the huge58 Antarctic ice sheet. Professor Rignot says the study will help experts
Scientists are learning new things about7 Antarctica, the coldest place on Earth8. For example, the Antarctic ice sheet9 is shrinking10. A new study found that summer ice loss in parts of Antarctica was at its highest level11 in 1,000 years. The study showed that Antarctic ice was melting12 mostly13 from below14 iceshelves15, where the water is warmer than16 the ice.
Ice shelves are the floating edges17 of the ice sheet – the ice cover18 - that extend over19 ocean waters. The study is the first complete look at all of the continent’s ice shelves.
Eric Rignot is an earth20 system expert at the University of California, Irvine. He also works for the American space agency,NASA. There he serves as senior research scientist21 at NASA’s Jet Propulsion Laboratory22, also in California.
He says ice melting from below is responsible for 55 percent of the shelf loss from 2003 to 2008. That is a much higher rate23 than scientists thought24 earlier25.
“We find that the melting of the underside26 of the ice shelves is even larger than27 the production of icebergs. So it is the dominant process of mass28 removal29 in the Antarctic.”
Professor Rignot and his team used satellite observations, radar and computer models to measure features30 above the ice to learn what was going on31 below.
“That includes the velocity of the ice, the thickness32 of the ice, how fast33 the “freeboard” (height34 of ice above sea level35) of the iceshelf is changing with time and also how much snowfall36 there is on the top of the ice shelves.”
The measurements37 show differences from one area to the next38 around the continent. The major ice shelves are called Ross, Filchner and Ronne. They make up two-thirds39 of Antarctica’s ice shelves. But they are responsible for only 15 percent of the melting ice.
At the same time40, about41 ten smaller ice shelves produced half the total water from ice melting during42 the same period. The smaller ones43 are found along the edges44 of comparatively warm water. Professor Rignot describes45 the importance of the information.
“That means46 that during warming47 of the climate where the properties48 of the Southern Ocean are changing, they may be changing faster than49 other oceans in the world. We may be in a situation where the coastline50 of Antarctica may be changing at a faster pace51 than we thought in the past.”
The professor says even small changes, like changes in ocean flow52 driven by wind53, can make a huge54 difference in the melting of the ice shelf.
“If the wind regime changes in the Southern Ocean, it is going to change the way the ocean heat55 is distributed on the coast. And that’s going to affect glaciers56.”
Sixty percent of the Earth’s fresh water57 is held in the huge58 Antarctic ice sheet. Professor Rignot says the study will help experts
Predict59 how the continent reacts to60 warmer ocean waters and helps to cause
rising sea levels61 around the world.
The study was published in the journal Science.Vocabulary
1. summer = verão
2. ice loss = perda de gelo
3. unrest = agitação
4. has hurt = tem prejudicado
5. has led to = tem conduzido a
6. formerly = anteriormente
7. learning new things about = aprendendo novas coisas sobre
8. the coldest place on Earth = o lugar mais frio na Terra
9. ice sheet = camada de gelo
10. shrinking = encolhendo
11. highest level = nivel mais alto
12. melting = derretendo
13. mostly = em sua maior parte
14. below = abaixo de
15. iceshelves = plataformas de gelo
16. warmer than = mais quente do que
17. floating edges = bordas flutuantes
18. cover = cobertura
19. extend over = estende-se sobre
20. earth = Planeta Terra
21. research scientist = cientista de pesquisa
22. Jet Propulsion Laboratory = Laboratório de propulsão a jato
23. much higher rate = índice muito mais alto
24. thought = pensavam
25. earlier = anteriormente
26. underside = lado de baixo
27. even larger than = ainda maior do que
28. mass = massa
29. removal = remoção
30. measure features = medir características
31. what was going on = o que estava acontecendo
32. thickness = espessura
33. how fast = o quão rápido
34. height = altura
35. above sea level = acima do nivel do mar
36. snowfall = queda de neve
37. measurements = medidas
38. from one area to the next = de uma area para a outra
39. make up two-thirds = constituem dois terços
40. at the same time = ao mesmo tempo
41. about = aproximadamente
42. during = durante
43. The smaller ones = os menores
44. Edges = beiradas
45. describes = descreve
46. means = significa
47. warming
48. properties = propriedades
49. may be changing faster than = podem estar mudando mais rapido do que
50. coastline = linha costeira
51. pace = ritmo, velocidade
52. ocean flow = fluxo do oceano
53. driven by wind= impulsionado pelo vento
54. huge = imenso
55. heat = calor
56. glaciers = geleiras
57. fresh water = água doce
58. huge = imenso(a)
59. predict = prever
60. reacts to = reage a
61. rising sea levels = elevação do nivel do mar
