World Rainfall Distribution Seasonal Changes Monsoons

The distribution of rainfall by latitude over the globe at the present epoch is shown in fig. 15. The greatest total is yielded by the equatorial rains, produced in the massive uplift of air and towering clouds in the zone of colivergence between the wind systems of the two hemispheres the socalled intertropical convergence. The moisture content of the air is greatest in this zone because of the enormous uptake by evaporation from the warmest oceans in the world (and also into the warm air from...

More Basic Matters

As to the underlying causes of the variations of the wind and ocean circulations which we observe, these may be largely a matter of the global temperature level and the strength and positions of the main thermal gradients. This interpretation is basic to our understanding of the seasonal changes of the wind circulation each year from summer to winter and back again, and is supported at least in outline by mathematical modelling of the atmospheric circulation. It is demonstrated in the sequence...

Weather Systems

It is at points of imbalance in the flow of the winds in the circumpolar vortex, as the air moves into regions where the pressure gradient is stronger or weaker and is accelerated or decelerated, as the case may be , or into regions where its path becomes more or less curved, that the wind fails to conform so well to the pattern of the lines of equal pressure. In these regions therefore movements take place which change the atmospheric pressure over the lowest layers of the atmosphere, piling...