The general circulation of the atmosphere: an evolving problem

We trace the development of the prevailing ideas about the general circulation of the atmosphere from the middle 17th century up to 1970. During this time, a quantity U, representing the extent to which we have not yet explained those features of the circulation of which we are aware, appears to have gone through four distinct cycles. Since 1970, no additional cycles are apparent, and the outstanding feature of the new work seems to be diversification. We propose that the study of the general circulation is a chaotic process, so that, at any time, the coming developments cannot be predicted with any assurance, even though many possibilities can be eliminated.