From Richardson to early numerical weather prediction

The development of computer models for numerical simulation of the atmosphere
and oceans is one of the great scientific triumphs of the past fifty years. These
models have added enormously to our understanding of the complex processes in
the atmosphere and oceans. The consequences for humankind of ongoing climate
change will be far-reaching. Earth system models are the best means we have of
predicting the future of our climate.

The basic ideas of numerical forecasting and climate modeling were developed
about a century ago, long before the first electronic computer was constructed.
However, advances on several fronts were necessary before numerical prediction
could be put into practice. A fuller understanding of atmospheric dynamics allowed
the development of simplified systems of equations; regular observations of the
free atmosphere provided the initial conditions; stable finite difference schemes
were developed; and powerful electronic computers provided a practical means of
carrying out the calculations required to predict the changes in the weather.

In this chapter, we trace the history of computer forecasting from Richardson’s
prodigious manual computation, through the ENIAC (Electronic Numerical
Integrator and Computer) integrations to the early days of operational numerical
weather prediction and climate modeling. The useful range of deterministic prediction
is increasing by about one day each decade. We set the scene for the story
of the remarkable progress in weather forecasting and in climate modeling over
the past fifty years, which will be treated in subsequent chapters.