Monthly Weather Review

An image from the Monthly Weather Review, essentially a recap of the weather in the previous month.  While this makes a lot of sense in the pre-internet age, somehow the journal is still published today. From the January edition in 1873:

The monthly rainfall returns for January from the Signal Service stations show that there has been in general a deficiency on the Pacific coas; but east of the Rocky Mountains an excess of rain and snow… The mean temperatures for January, as given by the Signal Service reports, show that over the country east of the Rocky Mountains the weather has been generally coler than usual.

Above from a particularly stormy November, 1950.

Computational Grids

From Turing’s Cathedral (pg 172-3), describing a giant lattice covering the entire surface of the Earth:

If Laplace’s mathematical intelligence were replaced by a computing machine of unlimited speed and capacity, and if the atmosphere below 100km were spanned by a computational lattice whose mesh size were less than the scale of the smallest turbulent eddy, say one millimeter… [all predictions would prove inaccurate after one month] not because of quantum indeterminacy, or even because of macroscopic errors of observation, but because the errors introduced into the smallest turbulent eddies by random fluctuations on the scale of the mean free path (ca 10-5mm at sea level), although very small initally, would grow exponentially… The error progresses from 1mm to 10km in less than one day, and from 100km to the planetary scale in a week or two.

Jule Charney and Walter Munk’s paper presented at the Conference on the Computer and the Development of Science and Learning, Institute for Advanced Study June 6 to June 8, 1972 (sadly, I couldn’t find a text for the paper online – for a full reference, see MIT’s archive).