History of numerical weather prediction – Wikipedia

December 29, 2021

https://en.wikipedia.org/wiki/History_of_numerical_weather_prediction
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In 1922, Lewis Fry Richardson published the first attempt at forecasting the weather numerically. Using a hydrostatic variation of Bjerknes’s primitive equations,[2] Richardson produced by hand a 6-hour forecast for the state of the atmosphere over two points in central Europe, taking at least six weeks to do so.[3] His forecast calculated that the change in surface pressure would be 145 millibars (4.3 inHg), an unrealistic value incorrect by two orders of magnitude. The large error was caused by an imbalance in the pressure and wind velocity fields used as the initial conditions in his analysis.[2] The first successful numerical prediction was performed using the ENIAC digital computer in 1950 by a team led by American meteorologist Jule Charney. The team include Philip Thompson, Larry Gates, and Norwegian meteorologist Ragnar Fjørtoft, applied mathematician John von Neumann, and computer programmer Klara Dan von Neumann, M. H. Frankel, Jerome Namias, John C. Freeman Jr., Francis Reichelderfer, George Platzman, and Joseph Smagorinsky.[5][6][7] They used a simplified form of atmospheric dynamics based on solving the barotropic vorticity equation over a single layer of the atmosphere, by computing the geopotential height of the atmosphere’s 500 millibars (15 inHg) pressure surface.[8] This simplification greatly reduced demands on computer time and memory, so the computations could be performed on the relatively primitive computers of the day.[9] When news of the first weather forecast by ENIAC was received by Richardson in 1950, he remarked that the results were an “enormous scientific advance.”[2] The first calculations for a 24‑hour forecast took ENIAC nearly 24 hours to produce,[2] but Charney’s group noted that most of that time was spent in “manual operations”, and expressed hope that forecasts of the weather before it occurs would soon be realized.[8]
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