The U.S. desperately needs a better way to predict storms. One scientist might have the solution
By Thomas E. Weber
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To understand [the modelling system] FV3, you first need to know how weather-forecasting models work. First, a computer creates a mathematical picture of the current state of the atmosphere based on real-world observations of air pressure, temperature and moisture from the multibillion-dollar global infrastructure of satellites, radar, weather stations and sounding balloons.
Next, using equations that describe the movement of air, the computer crunches numbers to step forward in time—-calculating what the atmosphere will look like a few minutes in the future. Keep feeding those numbers back into the equations, and you can predict further out in time. It’s all governed by the laws of physics, much the same way a video game can simulate the arc of a basketball thrown across an imaginary court.
What Lin and his team have done is devise a better, more accurate way for the computer to organize that picture of the atmosphere and how it behaves—the so-called dynamical core of the model. While the current American model uses a “spectral model,” where the atmosphere is represented by mathematical waves, FV3 (“Finite Volume on a Cubed-Sphere”) divides the atmosphere into boxes. Each box of air might be a little different in temperature, humidity, pressure and movement. Each box also acts upon the other boxes touching it, and vice versa. This models the atmosphere more accurately.
America’s lagging prediction model is especially dangerous when you consider that disaster preparedness is as much a psychological exercise as a technological one. The general public now has more access to weather-forecast information than ever before. From weather geeks glued to their smartphone apps to ordinary citizens tuning- in to nonstop cable-TV coverage, there’s surprising awareness of discrepancies between the U.S. and European models-—and experts worry this is leading some amateurs to choose the predictions- they like best and disregard official advice on evacuations and precautions.
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