《新概念英语》第四册 Lesson 14 The Butterfly Effect
Lesson 14 The Butterfly Effect
Beyond two or three days, the world's best weather forecasts are speculative, and beyond six or seven they are worthless.
The Butterfly Effect is the reason. For small pieces of weather -- and to a global forecaster, small can mean thunderstorms and blizzards -- any prediction deteriorates rapidly. Errors and uncertainties multiply, cascading upward through a chain of turbulent features, from dust devils and squalls up to continent-size eddies that only satellites can see.
The modern weather models work with a grid of points of the order of sixty miles apart, and even so, some starting data has to guessed, since ground stations and satellites cannot see everywhere. But suppose the earth could be covered with sensors spaced one foot apart, rising at one-foot intervals all the way to the top of the atmosphere. Suppose every sensor gives perfectly accurate readings of temperature, pressure, humidity, and any other quantity a meteorologist would want. Precisely at noon an infinitely powerful computer takes all the data and calculates what will happen at each point at 12.01, then 1202, then 12.03...
The computer will still be unable to predict whether Princeton, New Jersey, will have sun or rain on a day one month away. At noon the spaces between the sensors will hide fluctuations that the computer will not know about, tiny deviations from the average. By 12.01, those fluctuations will already have created small errors one foot away. Soon the errors will have multiplied to the ten-foot scale, and so on up to the size of the globe.
生词和短语
预报间晴，有阵雨。
各家报纸都刊登了有关埃迪·多纳根神秘失踪的猜测性报道。
猛烈的 / 怒吼着的暴风雪
这场讨论迅速演变成愤怒的争吵。
孩子们已经开始学习乘法和除法了。
她的金发像瀑布似的披落在肩头。
这架飞机是为经受猛烈的气流而设计的。
塔里木盆地沙尘暴卫星云图特征分析
船在岛的北边遇到了狂飑。
但在大旋涡的研究上，他们的工作看来却殊途同归。
地图上的坐标方格数字为C8。
这些植物在高温潮湿的环境中才能生长得旺盛。
meteorologist [ˌmiːtiəˈrɑːlədʒɪst] n. 气象学家
meteorology + ist 名词后缀，表学家。
气象学家预测接下来的几天有小雨。
人患病后体温可能会上下波动。
10%至15% 的离差是可以接受的。
参考译文
世界上最好的两三天以上的天气预报具有很强的猜测性，如果超过六七天，天气预报就没有了任何价值。
原因是蝴蝶效应。对于小片的恶劣天气 -- 对一个全球性的气象预报员来说，“小”可以意味着雷暴雨和暴风雪 -- 任何预测的质量会很快下降。错误和不可靠性上升，接踵而来的是一系列湍流的徵状，从小尘暴和暴风发展到只有卫星上可以看到的席卷整块大陆的旋涡。
现代气象模型以一个坐标图来显示，图中每个点大约是间隔60英里。既使是这样，有些开始时的资料也不得不依靠推测，因为地面工作站和卫星不可能看到地球上的每一个地方。假设地球上可以布满传感器，每个相隔1英尺，并按1英尺的间隔从地面一直排列到大气层的顶端。再假定每个传感器都极极端准确地读出了温度、气压、温度和气象学家需要的任何其他数据。在正午时分，一个功能巨大的计算机搜集了所有的资料，并算出在每一个点上12：01、12：02、12：03时可能出现的情况。
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