蝴蝶效应
课文学习台
The Butterfly Effect
区分观点、依据、例子与限制，用自己的话准确重建论述。
课文精读第1 / 4段
本课原文与译文
展开完整文本 · 便于查阅与检索
第1段
Beyond two or three days, the world's best weather forecasts are speculative, and beyond six or seven they are worthless.
即使是世界上最好的天气预报，预报期超过两三天也只能算推测，超过六七天就没有价值了。
第2段
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.
原因就在于蝴蝶效应。任何对于小范围天气的预报很快就不准。而对于一个全球气象的预报员来说，雷雨和暴风雪也能算小范围。误差和不确定性增多，经过一连串湍流式的逐级放大，从小尘暴和小暴风，逐步发展到只能从卫星上才能观察到的席卷整个大陆的旋涡。
第3段
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 be 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 12.02, then 12.03...
现代气象模型使用间距为60英里左右的网格。即使如此 （间距不大），有些初始数据也不得不依靠推测，因为地面观测站和气象卫星监测不到所有地方。假设地球表面按 1英尺间距布满传感器，且按1英尺一层从地面一直放置到大气顶层。 再假设每个传感器都极为精准地给出温度、气压、湿度和气象学家所需要的任何其他度量的读数。在正午时分，一个具有无尽算力的计算机写入全部数据，并计算12时01分，12时02分，12时03分等时刻，在每一个地点将要呈现的天气情况。
第4段
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.
这部计算机仍然无法预测出一个月后的某一天，新泽西州的普林斯顿天气放晴还是下雨。在正午12点，传感器之间（1英尺）的距离会掩盖计算机没有获得的读数波动，即对于平均值的细微偏离。到 12时01分，这些波动就已经在1英尺远的地方造成了小误差。很快这种误差会倍增到10英尺的范围，如此这般，直至全球的范围。
学完这一课
选一个可以讨论的判断，说明依据，再加上一句限制或不同情况。
译文与解析据吴应时整理资料及本站首轮审校稿；词伙与练习提示为本站学习设计。原PDF第57—59页，2022年2月第2版。