ABSTRACT
Variations of the wind circulation come over as wide a range of frequencies and time-scales as those of the weather and climate. The most important patterns of variation are evidently those of the largest scales and which also show a noteworthy tendency to persistence. We are not concerned here just with the extremes of ice age and the warmest interglacial behaviour of the circulation, patterns which are stabilized by the inertia of the ice and snow surfaces on the one hand, and ocean temperatures, land vegetation and soil surface conditions on the other.
