NCEIV14 1-0724 Flashcards
Lesson 14
Lesson 14 The Butterfly Effect
Beyond two or t
Beyond two or three days, the world’s best weather forecasts are speculative, and beyond six or seven they are worthless.
The Butterfly E
The Butterfly Effect is the reason.
For small piece
For small pieces of weather – and to a global forecaster, small can mean thunderstorms and blizzards – any prediction deteriorates rapidly.
Errors and unce
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 weat
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
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 s
Suppose every sensor gives perfectly accurate readings of temperature, pressure, humidity, and any other quantity a meteorologist would want.
Precisely at no
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 wi
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 spa
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
By 12.01, those fluctuations will already have created small errors one foot away.
Soon the errors
Soon the errors will have multiplied to the ten-foot scale, and so on up to the size of the globe.
