16/06/2021

In Folha, Viana talks about the history of weather forecasting.

Foto: Pixabay

Reproduction of Marcelo Viana's column in Folha de S.Paulo

Despite being exempt from military service due to conscientious objection, Lewis Fry Richardson (1881-1953) volunteered to drive an ambulance on the battlefields of World War I. For three years, he dedicated his downtime in the trenches to thinking about how to improve weather forecasting. His book "Weather Prediction by Numerical Process," published in 1922, initiated scientific meteorology.

Richardson realized that time is a global phenomenon: it is not possible to understand it in one region without also analyzing neighboring regions, and those neighboring regions, and so on. He then proposed dividing the Earth's surface into thousands of "squares" and created numerical methods to calculate the evolution of time in each square, and to make the results globally compatible.

He also conceived the physical space where the calculations would be performed: "After so much heavy reasoning, can we play with a fantasy? Imagine a large theater whose floor and walls are painted with a map, in the form of a globe. Thousands of computers calculate the time of the region of the map where they are seated, but each computer only deals with one equation. In real time, small signs indicate the results obtained, so that neighboring computers can read them." At the time, "computers" were people, mostly women, who were considered more focused and reliable than men for performing complex calculations.

Richardson's dream was unfeasible for its time, of course, and his initial predictions were poor. But the architecture he conceived proved well-suited to electronic computing: the theater was replaced by the interior of supercomputers, in which thousands of processors solve different parts of equations, communicating in real time with each other. Along with advances in mathematics, this allowed what was previously little more than guesswork to be transformed into a science.

To read the full text, visit the newspaper's website.