Without computers weather forecasting as we know it today would not be possible. From simple desk calculators to complex supercomputers which perform trillions of calculations a second, information technology has been at the forefront of understanding the weather for decades.
Mathematics and weather
The idea of creating a weather forecast using dynamic equations was first put forward by English mathematician, Lewis Fry Richardson, in 1922. He realised the dynamics of the atmosphere could be modelled by doing thousands of equations, thus being able to predict the weather.
In a pre-computer age, however, the only way to apply his numerical method was by hand. He estimated it would take 64,000 people to perform the calculations needed to make a forecast in time for it to be useful. While this wasn't practical, Richardson's theory formed the basis for weather forecasting as technology improved.
First steps for technology
In the 1950s the Met Office acquired an electrical desk calculator - which was cutting edge technology at the time. A mathematician specially trained in computational methods was hired to work it and thus began the first efforts to fulfil Richardson's dream.
This was taken further when Met Office staff had access to a 'real' computer owned by catering company, J Lyons. Called Leo, the machine was bought to calculate the value of Lyons' bakery sales, but its power was harnessed to help speed up calculations needed to make a weather forecast.
The Met Office embraced the computer age in 1959, when a Ferranti Mercury, nicknamed Meteor, was purchased. Capable of doing 30,000 calculations a second, it was a major step forward in the evolution of making weather forecasts. For the first time, scientists were able to regularly use numerical methods to make their forecasts.
By building an understanding of the way the atmosphere works, equations are created which seek to mirror these processes. The equations, built out of lines of computer code, combine together to make 'models', which are effectively attempts to recreate the dynamics of the atmosphere through maths. They work by taking all the current weather observations available to understand the current situation and applying the model to see what might happen next.
As our understanding of the atmosphere improved and the number of weather observation inputs increased, the need for more computer power also grew. Thus the Met Office bought a new supercomputer in 1965, an English Electric KDF9, which could do 50,000 calculations a second. This leap in speed, of more than 60%, allowed for faster, more complex forecasts to be made.
This pattern of advancing technology and increasingly complex models continued, with the Met Office buying successively quicker computers every five to ten years. By 1982, our CDC Cyber 205 could do 200 million calculations a second, but by 1997 a Cray T3E was doing more than a trillion (1,000,000,000,000) a second.
Cray XC40 supercomputer
The Met Office’s latest supercomputer was fully installed by 2017.
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