Dynamic Forecasting by Numerical Process

Abstract

As meteorologists have long known, the atmosphere exhibits no periodicities of the kind that enable one to predict the weather in the same way one predicts the tides. No simple set of causal relationships can be found which relate the state of the atmosphere at one instant of time to its state at another. It was this realization that led V. Bjerknes in 1904 [1] to define the problem of prognosis as nothing less than the integration of the equations of motion of the atmosphere. But it remained for Richardson [12] to suggest in 1922 the practical means for the solution of this problem. He proposed to integrate the equations of motion numerically and showed exactly how this might be done. That the actual forecast used to test his method was unsuccessful was in no sense a measure of the value of his work. In retrospect, it becomes obvious that the inadequacies of observation alone would have doomed any attempt however well conceived, a circumstance of which Rich­ardson was aware. The real value of his work lay in the fact that it crystallized once and for all the essential problems that would have to be faced by future workers in the field and that it laid down a thorough ground­work for their solution.

Most of the work described in this article was performed under contract N6-ori-139, Task Order I, between the Office of Naval Research and The Institute for Advanced Study.