Last summer, when I was visiting NCAR, Warren Washington gave me some papers to read on the first successful numerical weather prediction, done on ENIAC in 1950, by a team of meteorologists put together by John von Neumann. von Neumann was very keen to explore new applications for ENIAC, and saw numerical weather prediction as an obvious thing to try, especially as he’d been working with atmospheric simulations for modeling nuclear weapons explosions. There was, of course, a military angle to this – the cold war was just getting going, and weather control was posited as a potentially powerful new weapon. Certainly that was enough to get the army to fund the project.
The original forecast took about 24 hours to compute (including time for loading the punched cards), for a 24-hour forecast. This was remarkable, as it meant that with a faster machine, useful weather prediction was possible. There’s a very nice account of the ENIAC computations in:
- Lorenz EN. Reflections on the Conception, Birth, and Childhood of Numerical Weather Prediction. Annual Review of Earth and Planetary Sciences. 2006;34(1):37-45.
…and a slightly more technical account, with details of the algorithm in:
- Platzman GW. The ENIAC Computations of 1950: Gateway to Numerical Weather Prediction. Bulletin of the American Meteorological Society. 1979;60:302–312.
So having read up on this, I thought it would be interesting to attempt to re-create the program in a modern programming language, as an exercise in modeling, and as way of better understanding this historic milestone. At which point Warren pointed out to me that it’s already been done, by Peter Lynch at University College Dublin:
- Lynch P. The ENIAC Forecasts: A Recreation. Bulletin of the American Meteorological Society. 2008;(January):1-11.
And not only that, but Peter then went one better, and re-implemented it again on a mobile phone, as a demonstration of how far Moore’s law has brought us. And he calls it PHONIAC . It took less than a second to compute on PHONIAC (remember, the original computation needed a room-sized machine, a bunch of operators, and 24 hours).
- Lynch P, Lynch O. Forecasts by PHONIAC. Weather. 2008;63(11):324-326.