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immagini - Uno strumento nuovo: l'elaboratore elettronico

1950. Per dimostrare la validità del calcolatore elettronico, von Neumann sceglie le previsioni meteorologiche elaborate per la prima volta secondo criteri numerici. Poiché la nuova macchina di Princeton era ancora in fase di realizzazione, venne impiegato l'ENIAC.

Tellus
A quarterly journal of geophysics

Numerical Integration of the barotropic Vorticity Equation

By J.G. Charney, R. Fjörtoft, J. von Neumann

The Institute for Advanced study, Princeton, New Jersey

(Manuscript received 1 November 1950

Abstract

A method is given for the numerical solution of the barotropic vorticity equation over a limite area of the earth's surface. The lack of a natural boundary conditions. These are determined by a heuristic argument and are shown to be sufficient in a special case. Approximate conditions necessary to insure the mathematical stability of the difference equation are derived. The results of a series of four 24-hour forecasts computed from actual data at the 500 mb level are presented, together with an interpretation and analysis. An attempt is made to determine the causes of the forecasts errors. These are ascribed partly to the use of too large a space increment and partly to the effects of baroclinicity. The role of the latter is investigated in some detail by means of a simple baroclinic model.