C. Sutcliffe (Weather and Climate) wrote: “It was from the study of the prevailing winds as they were observed, especially the surface winds from the days of world exploration in sailing ships, that the concept of the general circulation of the atmosphere, the most important concept in the whole of meteorology, arose.”
And, “If the general circulation is, by definition, a matter of average winds of the world it immediately embraces all the other major physical quantities and physical processes. One cannot go far in the study of winds without introducing the driving force, the pressure; and one cannot go far in the study of pressure without introducing air density and air temperature for the pressure of the air above. Again the study of temperature introduces energy and its transformation, the absorption and emission of radiation, evaporation and condensation and the conversion of latent heat: vertical motions introduce clouds and rainfall, and so on until the whole of weather science is drawn into the argument. Thus, a complete understanding of the general circulation of the atmosphere implies a complete understanding of every process in world climatology and it is for this reason that it may justifiably be called the central problem of the science.”
If I were to ask—What is the prime mover of this atmospheric circulation?, what might one answer? In C. Donald Ahrens very popular meteorology textbook—Meteorology Today 9th Ed—I find the statement: “We know the primary cause of the atmosphere’s general circulation is the unequal heating that occur between tropical and polar regions.”