LEWIS FRY RICHARDSON"S FORECAST FACTORY

At 7:00 am on May 20, 1910 weather balloons floated into the sky all across Central Europe, collecting data on temperature, barometric pressure, and wind speed at a variety of altitudes. Seven years later, an ambulance driver in the French army named Lewis Fry Richardson would use that data to build the first ever dynamic model of the weather. Working with only pencil, paper, and a slide rule, Richardson engaged in a complex and laborious battery of calculations with the aim of retrospectively predicting how conditions would evolve in one location, southern Germany, over a six hour period. Though Richard’s model proved false — it predicted that barometric pressure over Munich would rise 1,108 millibars, a world record, when in fact it remained steady — his methods form the the basis of modern weather prediction.

In his 1922 book Weather Prediction by Numerical Processes, Richardson proposed the creation of a global weather prediction facility, which he dubbed the “forecast factory.” It would employ some 64,000 human computers sitting in tiers around the circumference of a gigantic globe to calculate the constant flow of differential equations. A conductor situated on a pedestal in the center of the sphere would keep the human computers working in unison. From Richardson’s description of the factory, as it appeared in the January/February 2001 issue of American Scientist:

The walls of this chamber are painted to form a map of the globe. The ceiling represents the north polar regions, England is in the gallery, the tropics in the upper circle, Australia on the dress circles, and the Antarctic in the pit. A myriad of computers [humans, that is] are work upon the weather of the part of the map where each sits…. From the floor of the pit a tall pillar rises to half the height of the hall. It carries a large pulpit on its top. In this sits the man in charge of the whole theatre…. One of his duties is to maintain a uniform speed of progress in all parts of the globe. In this respect he is like the conductor of an orchestra in which the instruments are slide-rules and calculating machines. But instead of waving a baton he turns a rosy beam of life upon any region that is running ahead of the rest, and a beam of blue light upon those who are behindhand.

Apparently, even by Richardson’s own criteria, the task would have required closer to 200,000 human calculators.

[Acknowledgments to Margaret]