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时间:2006-04-18 16:00来源:互联网 提供网友:cfgxj   字体: [ ]

Scientists Improve Space Weather Forecast Accuracy



At one time, scientists thought the space between Earth and Sun was a vacuum. But we now know that the sun fills it with gusts1 of hot, electrically charged atomic particles called the solar wind. Sometimes this wind blows hard. When the Sun's outer layer is very active, it hurls2 nearly one-third of its gaseous3 matter outward at supersonic speeds.


The U.S. government's oceans and atmosphere agency NOAA, has a Space Environment Center to monitor these discharges. The center's director, Ernest Hildner, says intense solar emissions4 are not dangerous to people on the ground, but can be a hazard to airplane occupants and astronauts. They can also shut down satellites, power networks, communications, and other technical systems.


Ernest Hildner: When the Sun has a storm, an eruption5 of plasma6 and magnetic field, it smacks7 the Earth's magnetic field and it causes difficulties to our technological8 systems. That is what we think of as space weather.


Several U.S., European, and Japanese satellites have gone into orbit during the past decade to measure the Sun and its emissions. One of them is at a point where it can warn us that solar particles are just one hour away. Mr. Hildner says these spacecraft have improved short-term space weather predictions.


Ernest Hildner: We are still not much better than we were on the one day, two day, three day prediction, but on the one hour prediction, we are much better than 90 percent correct now.


However, new research could eventually lengthen9 the forecasts.


Scientists have long known that solar storms are generated internally by the sudden release of magnetic energy rising to the surface. Like a tightly twisted rubber band, the Sun's magnetic fields can suddenly snap into a new shape. Researchers have tried to predict solar storms by focusing on these magnetic patterns. But this method is not very reliable because they know that electrical currents must also be present. But how are they linked to magnetic fields to power large flares11?


New satellite data have provided answers to U.S. government scientists and colleagues from the aerospace12 firm Lockheed Martin.


They have revealed that magnetic fields merging13 at different angles to each other are the most likely to produce a flare10. Lockheed Martin physicist14 Karel Schrijver says this interaction creates more electrical current than normally associated with a magnetic field.


Karel Schrijver: We learned to recognize that it had to come up in the wrong orientation15, off with the alignment16 of what was already there, twisted, and come up, in fact, in such a way that it suggested to us that the field that came up was itself carrying new electrical currents into the atmosphere.


To discover this, Mr. Schrijver and his government colleagues compared magnetic maps of the sun from the U.S.-European SOHO spacecraft with Sun surface images from the American TRACE satellite.


He says scientists can now predict which magnetic fields will turn into solar flares with 90 percent accuracy about two days before an outburst.


Mr. Schrijver: About 90 percent of the cases we could tell which were carrying currents and which were not. Those that carried the large currents had had two-and-a-half times more flares and the typical flare was at least three times bigger. So ten times more flare energy came out of these regions.


The findings still do not permit forecasts of precisely17 when a flare will erupt, only whether one is likely to, much as the buildup of snow on a mountain increases the chance for an avalanche18. The director of solar studies at the U.S. space agency, Richard Fisher, says refinement19 of the research will improve predictions.


Richard Fisher: This is quite useful for spaceflight operations and flight planning. We have been able to understand where it is likely to have a flare and what the size is likely to be. We can also tell when it is not very likely. This has considerable value.


The findings are published in the Astrophysical Journal.


David McAlary, VOA news, Washington.



vacuum [5vAkjuEm] n. 真空空间

solar [5sEulE] adj. 太阳的

gaseous [5^AsiEs] adj. 气体的

supersonic speed 超音速

NOAA abbr. National Oceanic and Atmospheric20 Administration国家海洋和大气局

hazard [5hAzEd] n. 冒险

occupant [5Ckju:pEnt] n. 居住者

plasma [5plAzmE] n. 等离子体,等离子区

magnetic field 磁场

rubber band 橡皮圈

orientation [7C(:)rien5teiFEn] n. 方向

outburst [5autbE:st] n. 爆发

refinement [ri5fainmEnt] n. 改进


1 gusts 656c664e0ecfa47560efde859556ddfa     
一阵强风( gust的名词复数 ); (怒、笑等的)爆发; (感情的)迸发; 发作
  • Her profuse skirt bosomed out with the gusts. 她的宽大的裙子被风吹得鼓鼓的。
  • Turbulence is defined as a series of irregular gusts. 紊流定义为一组无规则的突风。
2 hurls 5c1d67ad9c4d25e912ac98bafae95fe3     
v.猛投,用力掷( hurl的第三人称单数 );大声叫骂
  • Jane really hurls herself into learning any new song, doesn't she? 对任何新歌,简都会一心一意去学,对吗? 来自《简明英汉词典》
  • The necromancer hurls a bolt of dark energies against his enemies. 亡灵法师向对手射出一道带着黑暗能量的影束。 来自互联网
3 gaseous Hlvy2     
  • Air whether in the gaseous or liquid state is a fluid.空气,无论是气态的或是液态的,都是一种流体。
  • Freon exists both in liquid and gaseous states.氟利昂有液态和气态两种形态。
4 emissions 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
  • Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
5 eruption UomxV     
  • The temple was destroyed in the violent eruption of 1470 BC.庙宇在公元前1470年猛烈的火山爆发中摧毁了。
  • The eruption of a volcano is spontaneous.火山的爆发是自发的。
6 plasma z2xzC     
  • Keep some blood plasma back for the serious cases.留一些血浆给重病号。
  • The plasma is the liquid portion of blood that is free of cells .血浆是血液的液体部分,不包含各种细胞。
7 smacks e38ec3a6f4260031cc2f6544eec9331e     
掌掴(声)( smack的名词复数 ); 海洛因; (打的)一拳; 打巴掌
  • His politeness smacks of condescension. 他的客气带有屈尊俯就的意味。
  • It was a fishing town, and the sea was dotted with smacks. 这是个渔业城镇,海面上可看到渔帆点点。
8 technological gqiwY     
  • A successful company must keep up with the pace of technological change.一家成功的公司必须得跟上技术变革的步伐。
  • Today,the pace of life is increasing with technological advancements.当今, 随着科技进步,生活节奏不断增快。
9 lengthen n34y1     
  • He asked the tailor to lengthen his coat.他请裁缝把他的外衣放长些。
  • The teacher told her to lengthen her paper out.老师让她把论文加长。
10 flare LgQz9     
  • The match gave a flare.火柴发出闪光。
  • You need not flare up merely because I mentioned your work.你大可不必因为我提到你的工作就动怒。
11 flares 2c4a86d21d1a57023e2985339a79f9e2     
n.喇叭裤v.(使)闪耀( flare的第三人称单数 );(使)(船舷)外倾;(使)鼻孔张大;(使)(衣裙、酒杯等)呈喇叭形展开
  • The side of a ship flares from the keel to the deck. 船舷从龙骨向甲板外倾。 来自《简明英汉词典》
  • He's got a fiery temper and flares up at the slightest provocation. 他是火爆性子,一点就着。 来自《现代汉英综合大词典》
12 aerospace CK2yf     
  • The world's entire aerospace industry is feeling the chill winds of recession.全世界的航空航天工业都感受到了经济衰退的寒意。
  • Edward Murphy was an aerospace engineer for the US Army.爱德华·墨菲是一名美军的航宇工程师。
13 merging 65cc30ed55db36c739ab349d7c58dfe8     
  • Many companies continued to grow by merging with or buying competing firms. 许多公司通过合并或收买竞争对手的公司而不断扩大。 来自英汉非文学 - 政府文件
  • To sequence by repeated splitting and merging. 用反复分开和合并的方法进行的排序。
14 physicist oNqx4     
  • He is a physicist of the first rank.他是一流的物理学家。
  • The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。
15 orientation IJ4xo     
  • Children need some orientation when they go to school.小孩子上学时需要适应。
  • The traveller found his orientation with the aid of a good map.旅行者借助一幅好地图得知自己的方向。
16 alignment LK8yZ     
  • The church should have no political alignment.教会不应与政治结盟。
  • Britain formed a close alignment with Egypt in the last century.英国在上个世纪与埃及结成了紧密的联盟。
17 precisely zlWzUb     
  • It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
  • The man adjusted very precisely.那个人调得很准。
18 avalanche 8ujzl     
  • They were killed by an avalanche in the Swiss Alps.他们在瑞士阿尔卑斯山的一次雪崩中罹难。
  • Higher still the snow was ready to avalanche.在更高处积雪随时都会崩塌。
19 refinement kinyX     
  • Sally is a woman of great refinement and beauty. 莎莉是个温文尔雅又很漂亮的女士。
  • Good manners and correct speech are marks of refinement.彬彬有礼和谈吐得体是文雅的标志。
20 atmospheric 6eayR     
  • Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
TAG标签:   voa  环境科学  探索  天气预报  准确性
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